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^^^H^ A 757
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CLEAN WATER
HOW TO GET IT
1
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ALLEN HAZEN
1
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. -X .-
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WORKS OF ALLEN HAZEN
PUBLISHED By
JOHN WILEY & SONS
The Filtration of Public Water-Supplies.
Third Edition, Revised and Enlarged. 8vo, xii
+321 pages, fully illustrated with line and half-
tone cuts. Cloth, $3.00.
Clean Water and How To Get It.
Large 12mo, vi + 17^ pages, containing 14 full-
page half-tone illustrations. Cloth, $1.£0.
By WILLIAMS and HAZEN
Hydraulic Tables.
Showing the Jjosa of Head due to the Friction
of Water Flowintr in Pipes, A(^ueducts, Sewers,
etc., and the Discharge over Weirs. By Gardner
S. Williams. M. Am. Soc. C. E . of Michigan,
and Allen Hazen, M. Am. Soc. C. E. 8vo, iii +
75 pages. Cloth. $1.50.
Interior of covered pure-water reservoir at Washington, I). C.
before being filled with water. It is covered for the purpose of
keeping the filtered water clean.
1 '. .••••• ;'•! Frontispiece
CLEAN WATER
AND
HOW TO GET IT
BY
ALLEN HAZEN
OP THE American Scx:ibty of Civil Engineers, The Boston
Society op Civil Engineers, The American Water Works
Association, The New England Water Works Associa-
tion, The American Public Health Association,
The Society of Arts, etc.
FIRST EDITION
SECOND THOUSAND
NEW YORK
JOHN WILEY & SONS
45 EAST NINETEENTH STREET
London; CHAPMAN & HALL, Limited
1909.
Copyright. 1907
By ALLEN HAZEN
9I(» Mmttfic f »••
TO
THE BRISBANE BOARD OF WATERWORKS
IN WHOSE SERVICE WAS MADE
THE VOYAGE ON WHICH THESE PAGES
WERE WRITTEN
1
t
s
\
3
^
PREFACE.
Tms Kttle volume deals with the means now used by
American cities to secure clean water, and with the
application of these means to new problems.
Some closely allied subjects are also touched upon, in-
cluding some matters of general policy, pressure, and fire
service, the sale of water, and the financial management
of water works. This is because an imderstanding of
these matters is often necessary to enable the means of
securing a new supply, or improving an old one, to be
fully considered.
Matter descriptive of existing works and their manage-
ment is freely used where principles can be best shown
by it; but the object is to illustrate principles, and not to
describe the works that are mentioned.
Its object is to help beginners to imderstand some-
thing of first principles. Members of water boards, and
water works superintendents, have largely passed this
stage, and it is therefore not for them.
It is intended for those who have power to act, and to
act in a way to bring about better conditions. It is
therefore especially for mayors and aldermen who have
great responsibilities in these matters.
It is especially for those of them who have been drawn
from walks of life, in which they have had no water
works' experience, and who, wishing to serve their cities
well, can perhaps be aided in doing it, by very simple
statements as to some matters, '
S.S. AORANGI, PAaFIC OCEAN
March ii^ /907.
246308
CONTENTS.
Pagb
CHAPTER I.
Impounding Reservoir Supplies..
CHAPTER II.
Water Supplies from Small Lakes 26
CHAPTER III.
Supplies from the Great Lakes 29
CHAPTER IV.
Water Supplies from Rivers 32
CHAPTER V.
Ground Water Supplies 42
CHAPTER VI.
On the Action of Water on Iron Pipes and the
Effect thereof on the Quality of the Water 59
CHAPTER VIL
Development of Water Purification in America.. 67
CHAPTER Vin.
On the Nature of the Methods of Purifying Water 82
vii
• ••
Viu CONTENTS
Pagb
CHAPTER IX.
On the Application of the Methods of Water
Purification, Arranged According to the Mat-
ters TO BE Removed by the Treatment 92
CHAPTER X.
Storage of Filtered Water 114
CHAPTER XI.
On the Required Sizes of Filters and Other
Parts of Water Works 116
CHAPTER XII.
As TO the Pressure under which Water is to be
Delivered 123
CHAPTER XIII.
On the Use and Measure-ment of Water 133
CHAPTER XIV.
Some Financial Aspects 149
CHAPTER XV.
The Laying Out and Construction of Works 157
CHAPTER XVI.
On the Financial Management of Publicly Owned
Water Works 163
LIST OF ILLUSTRATIONS.
FACING PAOB
Interior of covered pure-water reservoir at Washington, D. C,
before being filled with water. It is covered for the pur-
pose of keeping the filtered water clean Frontispiece
The Old Croton Dam. This view was taken before the filling of
the New Croton Dam, which now entirely submerges the
old dam 2
High Bridge in 1907. Built about 1840 to carry Croton water
across the Harlem River to New York City 2
The new Croton Dam holding back water for the supply of *
New York City 4
One of the Boston Pumping Stations 8
Wachusett Dam of the Metropolitan Water Works for Boston
and Suburbs 8
Tubercles Growing in Iron Water-pipes 60
An early type of Mechanical Filter at Chattanooga, Tenn 76
The Little Falls Filters of the East Jersey Water Company 76
General View of Washington Filters. The filters are covered
and the top is grassed over and used as a park 78
Interior view of a filter at Washington, showing the hydraulic
removal of the surface layer of dirty sand 78
Interior of Filter House. Little Falls Filters of the East
Jersey Water Company, showing operating table for
mechanical filters 86
Bottom of a mechanical filter at Watertown, N. Y., with the
sand removed to show the water and air piping and
Btrainers 86
IX
f.
X LIST OF ILLUSTRATIONS.
FACING PAQB
Aeration of Missouri River Water in passing from one
settliog basin to another at Omaha, Neb 88
Aeration of water in falling over a stone dam 88
Coagulating Devices at Watertown, N. Y 90
Covered coagulating basins and mechanical filters in course of
construction at Watertown, N. Y 90
Aeration of Hemlock Lake water at Rochester, N. Y., resulting
in a reduction of tastes and odors 94
Hydraulic washing of dirty sand from sand filters, Washing-
ton, D. C 94
Intermittent filters at Springfield, Mass., showing one filter
out of use and being cleaned 96
Intermittent filters at Springfield, Mass., showing aerfition of
water at entrance and the distribution of the water to the
four filters 96
Coagulating and sedimentation basin with aeration of entering
water and with thorough bafiSing to assist sedimentation.
South Pittsburgh filters 102
Coagulating and sedimentation basin with bafiSes and pumping
station and filter house at St. Joseph, Missouri 102
Softening plant for reservoir water at Oberlin, Ohio 114
Interior of covered pure- water reservoir at Watertown, N. Y. . 11,4
CLEAN WATER AND HOW
TO GET IT.
CHAPTER I-
IMPOUNDING RESERVOIR SUPPLIES.
Croton Works of the City of New York. In the year
1842, when New York City had a population of about
3SSi00o> Croton water was first brought to the city. It
had taken seven years to build the works. The water
was taken from the Croton River through an aqueduct
41 miles long to the city. This aqueduct was 8 feet 5 J
inches high, 7 feet 5 inches wide, had a slope of 12.6
inches per mile, and was capable of carrying 95,000,000
gallons of water per day. This aqueduct crossed the
Harlem River which separates Manhattan Island on
which the city stands from the mainland on a masonry
arched bridge, called High Bridge, which to-day, sixty-
five years afterward, is one of the most notable of the
engineering works of the metropoUs.
In the city were built reservoirs to receive and hold
the water, and from them it was piped through the streets.
Afterwards, in 1890, a much larger aqueduct was put
in service, capable of bringing 300,000,000 gallons of
water per day from the Croton River.
A dam was built across the Croton River at the point
I
2 IMPOUNDING RESERVOIR SUPPLIES.
of intake, raising the water some 40 feet, or 26 feet above
the top of the aqueduct. The use of this dam was prin-
cipally to raise the water to the required elevation; but
it also served to a slight extent to hold back and store
water when an excess was flowing in the river and make
it available when there would not otherwise have been
enough.
When the Croton works were built the city used
12,000,000 gallons of water per day, and the natural
flow of the river was sufficient. The Croton River is a
relatively small stream. Above the intake it drains an
area of 360 square miles. This is equal to a square with
sides of 19 miles each.
The area from which water is taken to supply a city
is called in England a catchment area, and commonly in
the United States a watershed. The English term is
more accurate and better.
In dry weather the flow of the Croton River was not
very large, and as the city grew and needed more water
it soon happened that there were times when there was
not enough.
The city then began to build storage or impounding
reservoirs. Dams were built across various tributaries of
the Croton River, forming artificial lakes behind them.
The larger of these dams were of solid masonry. The
smaller ones were often built more cheaply, and just as
well, of earthen embankments. These reservoirs filled
when the streams were in flood, and the water was let
out in dry times as it was needed.
These reservoirs were not connected by pipes or aque-
ducts with the city. When water from them was wanted
Tbe Old Croton Dam. Thin vien- was taken before the filling of tlie
New CrotOD Dam, which now entirely Rubmergee the old dam.
'CDoTtesy ot W. H. Searg, Chief EnBiiMier Board of Aqueduct Commiagloaen.
, ft
••• •
* *
CROTON WORKS OF CITY OF NEW YORK. 3
the gates on their outlets were opened, and the desired
quantity of water was allowed to flow down the natural
channels until it came to Croton Lake, as the reservoir
formed by the dam first built was called.
Since then impounding reservoirs have been added to
the Croton system, one by one, as the needs of the city
have grown. The system, including two reservoirs now
building, is now complete, and it will not pay to add
others because those now available hold substantially all
the flood waters that can be practically utilized from the
catchment area.
The amount of water that can be utilized may be stated
in this way: On an average 46 inches of rain fall each
year upon the catchment area. Of this, one-half is lost
by evaporation from the water surfaces, from the sur-
face of the ground, and especially from the leaves of all
the plants and trees that grow upon it. The other half,
equal to a rainfall of 23 inches, flows off in the streams
and sooner or later reaches Croton Lake.
In wet years the amount that flows off Is greater, in
dry years it is less, than the average. In the winter and
spring months the flow is very much greater than at
other times.
Now, the principal use of the impounding reservoirs
is to hold the excess water of the winter and spring
flows and make it available during the summer and fall.
They also serve to a less extent to hold the water of
wet years and to make it available in dry years.
The reservoirs all together hold an amount of water
equal to a rainfall or runoff of about 16 inches upon the
entire catchment area, and it is computed that the
4 IMPOUNDING RESERVOIR SUPPLIES.
amount of water that can be continuously drawn from
the system by t-he aid of this storage through a dry time
is 17.5 inches per annum. This is equal to an average
flow of 300,000,000 gallons per day.
The whole average amount of water running off, as
measured through a long term of years, amounts to
about 23 inches, or 395,000,000 gallons per day, but
practically that part of this amount above the 300,000,000
gallons daily actually utilized cannot be made available.
To do it would require reservoirs of extraordinary size
to hold the excess from a series of wet years and make it
available in a series of dry years.
These reservoirs would cost too much in proportion to
the added quantity of water obtained. Further, the
gain would not all be utilized, first, because with added
water surface there would be more loss by evaporation;
and, second, because there would be a deterioration in
the quality of the water on holding it so long in reservoirs
which would be sometimes full and sometimes empty.
Catskill Supply for New York. A new source of supply
for New York City to supplement the Croton supply has
been authorized and is now under construction. The
catchment area is in the Catskill mountains, nearly a
hundred miles as the water flows from New York City
The part of the catchment area first developed is that
of Esopus Creek. This has zn area of 255 square miles.
It is thus considerably smaller than the Croton catch-
ment area. It is the plan, however, to divert several
neighboring areac whc:\ they cjre receded, and all the
works are built with reference to this end.
In one respect the development is quite different from
BOSTON SUPPLIES. 5
that of the Croton. Instead of providing a scries of
relatively small reservoirs, added from time to time as
the needs of the city require, the whole ultimate storage
will be provided by one enormous reservoir, called the
Ashokan Reservoir. This will hold 120,000,000,000
gallons of water, and will be the largest artificial reser-
voir for water supply in America, if not in the world.
This reservoir is much larger than it would pay to
build for the Esopus catchment area alone. It is built
so large in order that it may also serve to store water
from the other catchment areas which are to be later
diverted to it. It also differs from the Croton develop-
ment in the manner of drawing the water. All the
storage is in one reservoir, and the aqueduct to the
city leads directly from it, so that the flow through
the natural channel from the upper reservoirs to the
lower one on the Croton has no equivalent in the Esopus
plan.
Boston Supplies. Boston is also supplied with water
from impounding reservoirs upon relatively small streams.
The first of these reservoirs was Lake Cochituate, a
natural lake taken for the purpose of a reservoir, and
since then treated precisely as an artificial reservoir
would have been treated.
Cochituate water first entered Boston in 1848, when
the city had a population of 128,000, and the capacity of
the works first built was 9,000,000 gallons per day.
The Mystic works, also making use of a natural lake
as a reservoir, were abandoned in 1898, because of the
great increase in population upon the catchment area,
which was very near to the city.
6 IMPOUNDING RESERVOIR SUPPLIES.
The Sudbury River water first came to Boston in
1878, as an addition to the Cochituate supply. The
catchment area of this river was gradually developed by
a series of seven comparatively small reservoirs, added
from time to time in the same way that those upon the
Croton catchment area were added as needed.
The Sudbury supply becoming inadequate, a further
large addition was made in the Wachusett Reservoir,
upon the south branch of the Nashua River. The
Wachusett water first entered Boston in 1898. As in
the case of the new supply for New York, all the storage
is in one great reservoir, the Wachusett Reservoir, hold-
ing 63,000,000,000 gallons of water. When first built
it was the largest artificial reservoir in existence. It
was cheaper to build one large reservoir than a series of
smaller ones of the same total capacity; and as the
resources and growth of the city justified a complete
development in this respect at the outset, it was clearly
best to do it in this way.
Other Impounding Reservoir Supplies. Baltimore is
supplied from impounding reservoirs upon the Gunpow-
der River, and many large and small cities in the Eastern
states are similarly suppUed. Among them are Newark
and Jersey City, New Jersey; Worcester, Cambridge,
and Springfield, Massachusetts; New Haven and Hart-
ford, Connecticut; Altoona, Pennsylvania, and many
others.
Reservoirs only Partially Connected with their Catch-
ment Areas. Many impounding reservoirs have been
built larger than could be filled from the catchment areas
naturally tributary to them, and additional areas have
IMPOUNDING RESERVOIRS WITH PUMPING. /
been made partially tributary to them to insure their
being filled. At Hartford, Conn., for example, side-hill
or contour ditches are used to considerably extend the
natural catchment areas.
It only occasionally happens that the channels pro-
vided in such cases are large enough to carry the largest
flood flows or tight enough to hold all the dry weather
flows. Usually, therefore, more or less water is lost in
such connections, and the quantity of water available is
correspondingly less.
At Lynn, Mass., an additional area is made available
by means of pumps which lift water when the natural
flow is sufficient from the Saugus River to a reservoir too
large to be filled from its own catchment area. The
Staines reservoirs for London, England, operate in the
same way; that is to say, the flood flows of the Thames
are pumped to them, to be let out again when there is
need of the water.
Impounding Reservoirs with Pumping. By far the
greater number of impounding reservoirs are elevated
above the cities which they serve, and water flows from
them by gravity to the places where it is to be used. But
there are cases where the reservoirs are not high enough
to allow this to be done. This is particularly the case
along the sea-coast, and in general where the ground is
comparatively flat and the catchment areas but little
elevated above the cities which they serve.
Gloucester and Lynn, Mass., pump all their water
from impounding reservoirs located but little above tide-
level, and similar arrangements are in use at Charleston,
S. C, Norfolk, Va., etc.
8 IMPOUNDING RESERVOIR SUPPLIES.
Columbus, Ohio, should be mentioned in this connec-
tion. The Scioto River, with a catchment area of 1032
square miles above the water works' intake, usually, sup-
plies all the water that is needed. But in dry times there
is not enough water naturally flowing in the river. The
city has built a masonry dam 46 feet high, holding in
reserve 1,627,000,000 gallons of water to help maintain
the supply during dry times, with provision for increasing
the reservoir when the growth of the city requires it.
The Columbus supply, while in most respects to be
classed as a river supply, comes to a certain extent within
the class of impounding reservoirs which require pump-
ing.
Impounding Reservoirs in the West. Denver is sup-
plied in part with water from an impounding reservoir
upon the South Platte River. The dam is of stone
masonry, with a maximum height of 235 feet, and holds
24,000,000,000 gallons of water.
San Francisco and Oakland are also supplied from
large impounding reservoirs. Two or three years' sup-
ply are held in reserve in these cases. This is a far
larger allowance than is provided in most Eastern cities
where the reserve rarely reaches a year's supply, and
sometimes is only sufficient to last for a month or two.
The reason for the very great amoimt of storage needed
at San Francisco is to be found in the great inequality
of the rainfall. There are often years, and sometimes
two years in succession, when the natural runoflF is not
large enough to maintain the supply. Reservoirs must
therefore be provided to fill in the year when there is rain,
and to maintain the supply when there is but little rain;
Wachusett Dam of the Metropolitan Water Works for Boston
and Suburbs.
Courtsey ot Dextar Bmjkett, Chist Engineer Metropolitan Water Boud.
:V;
t>« •
COMPUTATION OF STORAGE REQUIRED. 9
and experience shows a reserve for a period of three years
to be necessary.
This is a far diflFerent condition from that of the East-
em states, where a substantial runoff can be counted
upon every winter.
Computation of the Amount of Storage Required. This
must be based upon records of runoff or flow of the
stream, for which calculations are to be made, covering
a series of years.
In case such records are not obtainable, as is often the
case, an estimate may be based on calculations resting
upon the actual records of streams which have been
measured and which are believed to be similar to the one
imder consideration.
Very good records of the flow of the Croton River are
available. There are also good records of the Sudbury
River. Both of these go back to about 1870. They are
particularly valuable because there were some very dry
years about 1881-3, and these records cover this period.
For more recent years there are more available records.
The runoff from the Wachusett catchment area, from
the Pequannock catchment area of the City of Newark,
and some others have been measured.
In addition, the United States Geological Survey has
measured the flows of many streams in the last years.
This work is most helpful, though unfortunately an
effort has been made to do more work than the means at
hand would permit to be done well, and many of the
results must be used only with considerable caution.
Rainfall records are easier to get and are much more
generally available than runoff records. They are of
*0 IMPOUNDING RESERVOIR SUPPLIES.
some help in comparing different streams, and especially
in comparing a given dry period for which the rimoff
has been observed with other dry periods for which
there are no rimoff records. Even in such cases rainfall
records are apt to be misleading, because there is no
close relation between observed rainfall and runoff. In
almost every long continued record it is foimd that the
year of least rainfall is not the year of least runoff.
In general it may be said that for Southern New Eng-
land, and for New York, south of the Catskill Moun-
tains, and for Northern New Jersey (and this is the
region in the United States where impounding reservoirs
have been most extensively used) fairly good estimates
of the amount of storage required to maintain a given
supply from a given catchment area may be made by a
proper application of the published figures of flow from
the Croton, Sudbury, and Wachusett catchment areas.
Outside of this region the data for computing runoff,
and the required amount of storage are less numerous
and less exact, and the accuracy of the computation must
therefore be less, even when made by the best qualified
engineers.
In a general way, within the limits above noted, with a
storage of 11.5 inches of runoff, or 200,000,000 gallons
of water per square mile of catchment area, a yield of
16.8 inches, or 800,000 gallons per day per square mile
may be coimted on, and one-half this quantity of water
can be secured with one-fourth this amount of storage,
as shown by the following table. Land* area only is
counted in these calculations, that part of the catchment
area which is covered with water being excluded, as the
CARE OF CATCHMENT AREAS.
II
evaporation from it nearly equals the rainfall in a dry
year.
Storage Required in Gallons per Square Mile of Land
Surface to Prevent a Deficiency in the Season of
Greatest Drought When the Daily Consumption is
as Indicated.
Daily Y
IBLD.
Storage Requirbd.
Gallons per sq. mile.
Inches per annum.
4.2
6.3
8.4
12.6
14.7
16.8
Gallons per sq. mile.
Inches of runoff.
200,000
300,000
400,000
500,000
600,000
700,000
800,000
10,000,000
30,000,000
50,000,000
75,000,000
100,000,000
140,000,000
200,000,000
0.6
1.7
2.9
4.3
5.8
8.1
"•5
It must be remembered that even within the limits of
area mentioned there is considerable difference in yield-
ing power of catchment areas, and these can be to some
extent allowed for when sufficient data are at hand.
It does not make very much difference in case of par-
tial development whether all of a catchment area is
tributary to the reservoir or only a part of it, provided
that the reservoir, and every reservoir, if there are more
than one, must have catchment area back of it, so that
the least winter runoff, which may be taken roughly at
12 inches, will completely fill it after it is empty.
The above figures apply only to the area mentioned.
In other parts of the country the conditions of runoff are
widely different.
Care of Catchment Areas. The catchment areas sup-
plying impounding reservoirs, and the natural ponds and
lakes used as reservoirs, are limited in area, when com-
pared, for example, with the catchment areas of the
12 IMPOUNDING RESERVOIR SUPPLIES.
great rivers from which many public water supplies are
drawn. It is, therefore, possible to inspect them in a
sanitary way and to keep track of what is taking place
upon them. It is usual for cities to devote some atten-
tion to this subject.
The ideal catchment area is free from human habita-
tion and is covered with forest. Lynn, Mass., and
Hartford, Conn., own all or practically all of the catch-
ment areas of some of their reservoirs, and are encour-
aging forests to grow upon them. It has not been
possible to extend this policy to all catchment areas.
This is because the growth of the cities is such that when
a certain catchment area is well in hand, another and
larger one must be taken to maintain the supply, and a
long time must elapse before that can be brought to the
standard.
It is often impossible to remove population from a
catchment area, and, in fact, it is usually unnecessary to
do so. Very good water is drawn from areas upon which
there is much population, when proper and well known
precautions are taken. There are 776 people per square
mile upon the Cochituate catchment area, 282 upon the
Sudbury, 49 upon the Wachusett, and 59 upon the Cro-
ton, yet it is not to be supposed that the waters drawn
are seriously impaired by these populations. And as
better means of handling the water are used, the influ-
ence of population upon the quality of the water becomes
less.
The storage of water in large reservoirs tends strongly
to improve its sanitary quality. Disease germs, if they
are present, die in water in such storage. In our climate,
CARE OF CATCHMENT AREAS. 1 3
at least, they never grow in storage reservoirs, and, if
introduced, the length of time that they can live is lim-
ited. This is practically what makes the Boston water
and the New York water relatively safe. The greatest
danger is that some polluted water will sometimes get by
the reservoir, or flow through it by some short cut, and
so reach the consumers before it has been subjected to
full storage conditions for a sufficient length of time.
Further, the influence of the population upon the qual-
ity of the water in the future will be less than it now is,
because it now seems clear that in order to improve the
physical character of the water, as will be explained at
length, the water of these reservoirs is sure to be sub-
jected to some process of purification before delivery,
and when this is done such effects of pollution as there
may be will largely be removed at the same time and by
the same means.
There is therefore no real reason for attempting to
turn back into their primeval forested state the cultivated
and populated areas from which it is necessary to take
the water to supply our cities. The practice of Boston,
New York, and many other cities is sufficient, and this
practice may be briefly stated as follows :
There is a sanitary inspector who makes himself
familiar with the whole catchment area. Suitable laws
give authority. Manufacturing wastes and human
wastes are kept out of the main streams and the smaller
tributaries of the catchment areas. Where expense is
involved to remove old sources of pollution, the city
pays it, and new sources of pollution are not permitted.
The city owns the shores of the reservoirs, and also
14 IMPOUNDING RESERVOIR SUPPLIES.
often the land along the more important streams. Some-
times properties that are especially likely to pollute the
water, as, for example, old mills using water power, are
acquired by purchase or condemnation. In these ways
the grosser pollutions are kept out of the water by the
city, and the rural population upon the catchment area
remains comparatively undisturbed.
The purchase of all unoccupied lands on the catch-
ment areas, which can be bought at fair prices, is often
to be recommended, but it has not often been carried
out.
The development of manufacturing and suburban
centers upon catchment areas, especially where there is
good train and trolley service, and other favorable con-
ditions, is more to be feared. Such developments will
no doubt lead ultimately to the abandonment of some of
the Boston catchment areas, and perhaps at a later date
of the Croton, and some others, and the substitution of
other, larger and more remote areas.
But the possibilities of water purification, as yet but
slightly realized, must be taken into account, and it may
be a long time before this happens.
Stagnation of Water in Impounding Reservoirs. In
our climate, when a reservoir or lake is more than from
20 to 40 feet deep, the upper part of the water is usually
in circulation under the influence of the wind, and the
lower part remains stagnant. There is little or no
mixing between the surface water and the bottom
water, except for two short periods each year, one
in the spring and one in the fall. These periods of
circulation to the bottom are known to water works
STAGNATION OF WATER. 15
men respectively as the spring turnover and the fall
turnover.
At the time of the spring turnover all the water mixes
from top to bottom and has a temperature approximately
that at which water has its greatest density, namely,
39° F. Afterwards the sun warms the surface water
above this temperature. This makes it lighter, and then
it will not go down again to mix with the colder and
heavier water below, but remains at the surface.
The wind stirs it up for a certain depth. This depth
is about 20 feet in small reservoirs and about 40 feet in
the great lakes. In this surface layer the temperature
may rise in midsummer at the surface to 75° or 80° or
more.
Below, the water is cooler, and some distance down
it rapidly falls to the temperature of the whole mass of
the bottom water. And this bottom layer to within 20
or 40 feet of the surface, depending upon the size of the
reservoir, remains quiet and stagnant and unmixed with
the surface water from spring until fall. Its temperature
gradually and slowly increases, but it is always cool and
still.
In the fall the temperature of the top water falls, until
it approaches that of the bottom water. As the differ-
ence is less the wind action extends deeper, until, all at
once, often when the wind is blowing, all the water in the
reservoir turns over and mixes from top to bottom. The
mixing continues for a few weeks, until the temperature
of the surface water falls below the point of maximum
density. Then the colder water commences to accumu-
late at the top. The top often freezes and entirely shuts
1 6 IMPOUNDING RESERVOIR SUPPLIES.
out wind action, so that the period of winter stagnation
is even more quiet than the summer period. It is ter-
minated by the warming of the surface water in spring,
until it reaches the temperature of the bottom water,
when the spring turnover again takes place.
Now, this phenomenon of stagnation has much to do
with the quality of the water.
y Without attempting to go into the chemistry of the
processes, the most important conditions are these: In
the brief period of circulation following the spring turn-
over, the water contains normally a large amount of oxy-
gen or air in solution, as does almost any pure natural
surface water. And when the period of summer stag-
nation sets in, the bottom water is well charged with this
oxygen. Now, on the sides and bottom of the reservoir,
in contact with this stagnant water, there is much organic
matter, and further quantities of organic matter settle
down from time to time from the warmer surface water.
These are in the form of the dead or living bodies of
organisms that have grown in the warm surface water
in the sunshine and have then sunk away from it into the
cool dead water below. Now, the organic matter on the
bottom, and that coming down from above, soon start
to ferment and decompose and become oxidized. That
is to say, they are converted back into their constituent
elements, and this is done at the expense of the oxygen
held in solution in the water. This oxygen lasts for a
time, but long before the summer is over it is all used up.
In the absence of oxygen (for there is no more below,
and without circulation there is no way that it can get
down from above) the organic matters still continue to
STAGNATION OF WATER. 17
decompose, but they decompose in another way. The
decomposition that takes place in the absence of oxygen
is called putrefaction. Now putrefaction produces some
vile odors and nasty tastes. It is largely because of
these odors and tastes that we are interested in it.
These odors and tastes accumulate in the bottom water
until the fall turnover; then they become mixed with
all the water in the reservoir. And if the water is drawn
from the reservoir near the top, as it usually is, there will
be a great change in the quality of the water on the day
of the fall turnover.
These odors and tastes will make an impression upon
the quality of the water at other times. Reservoir out-
lets at certain levels do not draw water from those levels
only, as is sometimes supposed. Instead, they draw
somewhat from all directions where there is water; from
above and from below, as well as from the plane of their
own levels. And so, in the natural course of events, even
though water is drawn only from the top, some bottom
water will be drawn with it, and the odors and tastes of
putrefaction will be carried to a greater or less extent
with it into the supply.
The odors and tastes of putrefaction are rapidly dis-
sipated and destroyed by exposure of the water containing
them to the air. But to effect this dispersion the expo-
sure must be in some active or even violent way, such as
playing through a fountain, or falling over a dam, or
flowing in a rapid, strong current down the natural bed
of a stream with a rapid fall.
In the Croton system this effect of aeration to disperse
the odors and tastes of putrefaction is used to a large
I« IMPOUNDING RESERVOIR SUPPLIES.
extent. Most of the storage reservoirs are high in ele-
vation above Croton Lake. When water from them is
needed, it is the bottom water which is mainly drawn.
This water, often foul smelling as drawn, rapidly cleans
itself as it flows through the outlet f oimtains and over the
rocky channels to the lower reservoir, from which it
flows to the city. The old Croton Lake was too small
to develop putrefactive action on its own account to an
objectionable extent, and so the city was substantially free
from the odors and tastes resulting from putrefaction.
The new Croton dam, making a reservoir taking the
place of the old Croton Lake, but vastly larger, has not
improved conditions in this respect. The results of
putrefaction in it are more noticeable in the city.
Putrefaction is not universal in stored waters. Many
lakes and a few very clean reservoirs are free from it.
^ Reservoirs less than 20 feet deep are kept in circula-
tion by the wind to the bottom all summer, and in general
the phenomenon of stagnation and putrefaction do not
take place in them. In many cases, however, with dirty
bottoms and strong growths of weeds and organisms,
putrefaction does take place in the lower part of even
quite shallow reservoirs. Unmistakable evidences of
this, for example, have been found in the Ludlow Reser-
voir at Springfield, Mass., and even in the extremely
shallow Goose Creek Reservoir at Charleston, S. C.
Odors and Tastes from Growths of Organisms. Many
kinds of organisms grow in impounding reservoirs, rang-
ing all the way from the humblest germ to the full-grown
fish and lily-pad. Most of these organisms do no
particular harm, but some of the kinds are extremely
ODORS AND TASTES. 1 9
troublesome. They are troublesome principally because
of the odors and tastes which they produce in the water.
Some of these come from essential oils which the organ-
isms produce and liberate during their growth, and some
of them result from the death and decay of the bodies of
the organisms. Some of the troublesome organisms feed
upon other organisms or their remains. These, in a general
way, may be compared to the higher animals. Some of
these may grow and become troublesome in winter under
the ice. But the most troublesome organisms are the
algae and other microscopic organisms which grow in
the sunlight near the surface of the water.
These organisms are comparable to the higher plants.
They do not depend upon organic matter or the bodies
of other organisms for their food supply. They require
only the carbonic acid and the nitrogen and the mineral
matters always present in the -vsjater and in the air, and
the sunshine for their growth. And from these simple
materials they build up the matters which compose their
bodies, and which give rise to the odors and tastes, just
as a tree builds up its own substance from the mineral
matter of the soil and the carbonic acid of the air, with
only the help of the sunshine.
Where there is considerable population upon the catch-
ment area of a pond or reservoir, the pollution reaching
the water from it serves as a food supply for certain
organisms and stimulates their growth to a noticeable
degree.
There are many kinds of algae, and they differ greatly
in their odor-producing powers. Practically all Ameri-
can impounding reservoir waters suffer from them, but
•^
20 IMPOUNDING RESERVOIR SUPPLIES.
some far more than others. English reservoirs seem to
be comparatively free from them, probably because of
the lower temperatures of the surface waters. English
reservoir surface temperatures do not often stay long
above 60° F» and seldom go above 65°. American reser-
voirs have temperatures fully 10° higher in summer, and
this seems to be the most important point of difference.
In some Australian impounding reservoirs, very high
surface summer temperatures are obtained, and strong
growths take place; but it does not appear that the odors
and tastes produced by sub-tropical conditions in Aus-
tralia, and in the southern part of the United States, are
as much more objectionable when compared with those
in the climate of New York, as might be reasonably in-
ferred from the very great increase in the amount of
such trouble in the climate of New York as compared
with English conditions..
Growths often do not occur in a particular reservoir
supply because it is not seeded, but there is no known
way of preventing seeding.
A certain degree of quiet and repose is necessary for
the development of the organisms. This is why they
never grow in rivers and flowing water. Wave action
from wind also prevents growth, and this seems to be
one reason why large lakes and reservoirs are less
troubled by them than smaller ones.
Most American impounding reservoirs are arranged to
have water drawn from their surface- layers, to avoid the
odors and tastes of putrefaction in the bottom water; but
it sometimes happens that the surface water is even
more objectionable than the bottom water because of
odors and tastes of living and dying organisms.
STRIPPING.
21
Stripping. In Massachusetts more attention has been
given to protecting the quality of reservoir waters than
elsewhere, with a view to avoiding objectionable odors
and tastes.
Shallow flowage has been cut out of many reservoirs,
partly by diking oflf shallow portions, and partly by
filling them with material excavated froia other shallow
portions. This has had the cflect of reducing the area
of a reservoir, and of increasing its average depth.
But by far the most extended and costly work has,
been the stripping. By stripping is meant the removal
of the surface soil from the area, that is to be covered^
with water. At least eight considerable reservoirs, in
addition to many smaller ones, have been stripped in
this way, namely:
Reservoir.
City supplied.
Area in
acres.
Average
depth
in feet.
Capacity* ,
in million
gallons.
Wachusett
Sudbury
Lower Hobbs . . .
Franiingham No. 3 .
Hopkinton ....
Upper Holden . . .
Ashland
Lower Holden . . .
Boston . . .
Boston . . .
Cambridge .
Boston . . .
Boston . . .
Worcester . .
Boston . . .
Worcester. ,
4,200
1,292
467
253
185
185
167
149
46
18
10
15
26
17
26
IS
63,100
7,253
1,450
1,183
1,521
794
1,464
742
The object of stripping has been to remove the organic
matter of the surface soil. Where this has been thor-
oughly done, it has tended to improve the conditions of
the water in the reservoir. In the older reservoirs pre-
pared in this way putrefaction in the bottom water has
not taken place for some years after the reservoirs were
built, although in other cases putrefaction seems not to
have been entirely prevented, even at the outset.
22 IMPOUNDING RESERVOIR SUPPLIES.
The removal of the soil also seems to cut off a part of
the food supply for objectionable organisms, and the
stripped reservoirs have suffered less from these growths
than other reservoirs similarly situated but not stripped.
But stripping does not prevent objectionable growths;
it only reduces them somewhat, and it does not always
permanently prevent putrefaction in the bottom water.
It does not prevent the growths, because some of the
worst of the organisms do not need or make use of
the organic matter of the soil as a food supply. Instead,
they live on the mineral matters of the water and the air,
and with the aid of the sunshine they build up their own
organic matter precisely as the higher plants do in grow-
ing in soil. Removing the soil from a reservoir site
does not seriously or permanently interfere with the
growth of these organisms. Further, it cannot be de-
pended upon to permanently prevent putrefaction, be-
cause in our climate there seems to be an inevitable
accumulation of organic matter on the bottom of all
ponds, except those which are so large that the wind
action is able to hold the growths of organisms down,
and the accumulation of the bodies of dead organism
on the bottom soon furnishes the materials for putre-
faction even though all soil with its organic matter was
removed at the start.
This accumulation comes from the bodies of organ-
isms which grow in the sunshine in the top water and
then settle through the stagnant bottom water to the
bottom. It IS inevitable and cannot be prevented. It
Is an accumulation of this general character which has
filled with peat most of the lakes that were left by the
THE USE OF COPPER SULPHATE. 23
glacial epoch, and has changed them into the peat
swamps so common in all our Northern states.
• Stripping is an expensive process, but the quality of a
public water supply is an important matter, and in some
cases the cost has been justified by the improved quality
of the water.
In other cases there seems to be no reason to doubt that
more improvement could be effected in other ways, at less
cost as, for instance, by aeration and filtration of the watei .
On the Use of Copper Sulphate. In 1904 Dr. George T.
Moore, of the United States Department of Agriculture,
proposed the use of sulphate of copper in impounding
reservoirs, to poison the organisms which produce objec-
tionable odors and tastes. This substance is extremely
poisonous to some of the organisms and only moderately
poisonous to man. It is therefore possible, with due
care, to kill the algse without endangering the health of
the people who use the water.
The method of treatment proposed and generally used
is to put weighed quantities of the copper sulphate in
loose cloth bags and tow them back and forth with row-
boats through the water of the reservoir until the material
is dissolved. One part of copper sulphate in from four
to ten million parts of water suffices to destroy growths
of some objectionable organisms. Others require larger
doses. Some of the copper combines with the bodies
of the organisms and settles with them to the bottom, and
in this way is removed from the water. If the water is
hard, more copper is removed in this way, and it goes out
quicker. If the water is afterwards filtered most of the
remaining copper is removed.
24 IMPOUNDING RESERVOIR SUPPLIES.
m
As copper is but slightly poisonous to man, there does
not seem to be any real danger in the use of copper in this
way, or even in the use of the somewhat larger doses
which have occasionally been used where the water was
very bad.
The copper kills some kinds of organisms, but not all
kinds, and to some extent its use clears the way for
stronger growths of the forms that are not killed. It
therefore changes the kind of growth in a reservoir to
some extent, and this change is frequently accompanied
by a great improvement in odors and tastes.
The use of copper sulphate does not prevent, or even
materially reduce, putrefaction, and the tastes and odors
resulting from it.
This method of treating water is cheap, easily and
quickly applied, and considerable good has come from it.
The correction is only partial, however, and not always
permanent. It is not therefore to be relied upon in all
cases.
Color in Reservoir Waters. Most reservoir waters
are colored yellow to a greater or less extent by peaty
matter. This coloring matter is extracted from dead
leaves, from soil, from peat, etc. . It seems to be the
same material as the coloring matter of tea, and it is
certainly harmless. But it makes a water less pleasing
in appearance, and great efforts have been rightly made
to prevent it and to remove it.
When a colored water is exposed to sunlight it is grad-
ually bleached. A long period of exposure is required
for completing bleaching, but a notable reduction in
color due to this cause is usually found in all considerable
COLOR IN RESERVOIR WATERS. 2$
impounding reservoirs. Some of the Boston reservoirs
have been made larger than would otherwise have been
necessary and desirable for the sake of allowing more
bleaching to take place in them.
A large part of the color comes from swamps upon
the catchment areas. When swamps are drained, the
color of the water issuing from them is reduced.
The upper Mississippi is a highly colored stream.
There are thousands of square miles of swampy land
upon its catchment area. In the last decade much of
this land has been drained to allow its use for agricul-
tural purposes. Only a fraction of the whole amount
of swamp area has been drained, but the change thus
far made has reduced to a noticeable extent the color of
the water of the river at Minneapolis.
In the Boston water works thousands of acres of
swamp upon the catchment areas of the various reser-
voirs have been drained by the city, with the consent of
the owners of the land, for the purpose of reducing the
color of the supply. A considerable reduction in color
has been so made.
If there were no other ways of reducing color, bleach-
ing in reservoirs and drainage of swamps would be
worthy of most careful attention and frequent use. But
at the present time other means of removing color are
known which usually accomplish more for a given ex-
penditure than can be reached in these ways. These
will be described in connection with methods of water
purification.
CHAPTER n.
WATER SUPPLIES FROM SMALL LAKES.
The city of Rochester takes its supply from Hemlock
Lake, thirty miles from the city and elevated above it so
that water flows by gravity under sufficient pressure. In
the same way the city of Syracuse uses the water of
Skaneateles Lake.
These cities were fortunate in finding these lakes,
which are really impounding reservoirs ready-made and
suitable for their needs. Some expenditures were nec-
essary to acquire the water rights, and to buy some of
the shores, and to secure sanitary protection of the qual-
ity of the water; but broadly speaking, these reservoirs
were gifts of nature to these cities, and if thiey had not
been there, the cities might, and probably would, have
spent hundreds of thousands, or millions, of dollars in
building reservoirs less suitable for their purposes than
those freely provided by nature.
In taking such a lake with a limited catchment area,
provision must be made for raising and lowering the
water surface within certain limits. This is done by
building a dam at the outlet, or by putting in an outlet
pipe at a lower level than the natui:al outlet, or by doing
both at once. This provides the necessary storage
capacity to hold the winter and spring flood-flows, and
26
NATURAL RESERVOIRS. 27
to allow them to be drawn and used when needed in the
dry summer months.
And when this is done the natural lake serves pre-
cisely the same purpose as an artificial reservoir, and
the water is subject to the same troubles. The sanitary
protection of the catchment area, the stagnation and
putrefaction of the bottom water, and the growth of or-
ganisms in the top water, are all pretty much the same
as in artificial reservoirs.
On the whole, the waters of natural lakes and ponds
are less subject to objectionable odors and tastes than
are the waters of artificial reservoirs, and putrefaction is
less troublesome, but the difference is one of degree, not
of kind.
Growths of organisms are less frequent and strong,
probably because the lakes are larger and deeper and
more completely subject to, and controlled by, wind
action, and putrefaction is less prevalent because there
are fewer organisms growing " in the top water and
settling down into the bottom water to cause it.
The advantages of taking a natural lake for a
reservoir are so great and obvious that it has nearly
always been done where circumstances have per-
mitted. Both New York and Boston have utilized a
number of lakes upon their catchment areas in
this way, though the reservoirs mainly depended
upon have been artificial. Portland, Maine, is sup-
plied from Sebago Lake. St. Paul is supplied from
a number of small lakes. In this case the lakes are
not high enough for a gravity supply, and the water
is pumped.
28 WATER SUPPLIES FROM SMALL LAKES.
Throughout the northern part of the United States,
where the country has been glaciated, and small lakes
abound, innumerable smaller cities and villages are sup-
plied from them, sometimes by gravity and sometimes
by pumping.
CHAPTER III.
SUPPLIES FROM THE GREAT LAKES.
Most of the cities on the shores of the Great Lakes
use water taken from them by pumping. The largest of
these cities in the United States are Chicago, Cleveland,
BufiFalo, Detroit, Milwaukee, and Duluth. They also in
general put their sewage into the same water from which
their supplies are taken. And the relations between the
water supply and the sewage are most interesting and
important.
In one respect two of the cities are more favorably
situated than the others. Buffalo and Detroit are upon
strong running streams at the outlets of the lakes, where
it is possible to take the water supplies from points
above the cities, and to discharge the sewage at points
below, with little likelihood of subsequent mixing. And
in this respect the water problems of these cities are
much simpler than those of the others.
BufiFalo has the advantage over Detroit that the water
comes to it more directly from the lake and with less
chance of pollution. Detroit is sixty miles below the out-
let of Lake Huron, and in that distance there is oppor-
tunity for much pollution. This pollution comes both
from the drainage of the considerable area reaching the
river in this distance and from the discharge of sewage
from the cities directly upon its banks. And this pollu«'
29
30 SUPPLIES FROM THE GREAT LAKES.
tion by sewage is an important matter even with a dUu-
tion as great as that in the Detroit Rivero
Milwaukee and Duluth are fortunate in that they are
able to reach the lakes with intakes in deep water at
points where there seem to be fairly definite currents
bringing fresh, clean water from the body of the lake to
the intakes, and excluding the city sewage. These cur-
rents seem to be dependable, although it may be that
they are sometimes reversed temporarily by strong winds.
Certainly the present indications are that the water
obtained from them is at least comparatively free from
sewage.
Chicago and Cleveland have suffered most from the
mingling of their own sewage with their water supplies,
and their troubles in this respect are not over. Chicago,
it is true, has cut a drainage canal to keep her sewage
from entering the lake, and to take it instead through
tributaries to the Mississippi River, at a cost of over
forty million dollars. But even now that the canal is in
operation, so much polluting material finds its way to the
lake that the water is polluted at times for a long distance
out. Cleveland has no drainage canal, but she is smaller
than Chicago, and the conditions of the water in the
lakes near the two cities probably are not greatly different.
Both lakes are comparatively shallow and are stirred
to the bottom by heavy winds, at least as far out as the
water works intakes have yet been built. Both cities
have spent millions driving tunnek out under the bot-
toms of the lakes for the purpose of securing water free
from contamination. Both have succeeded in getting
better water in this way, and both have failed to get
PROBLEM OF CONTAMINATION. 3 1
thoroughly good water, even with intakes located four
or five miles from shore; and both cities have suffered
severely at times, and perhaps a little all the time, from
sickness and death caused by the pollution of the lake
waters by their own sewage.
The Great Lakes are so large, and the dilution and
time intervals and exposure to sun and air are so great
that there is no chance of infection being carried from
one of the great cities to another. Chicago's sewage
would not endanger the purity of Detroit's water supply,
even with no drainage canal. The little city of St. Clair,
with 2543 inhabitants, only 45 miles away, is far more
dangerous to Detroit. In the same way Detroit's sewage
is harmless at Cleveland, and Cleveland's sewage is
harmless at Buffalo.
Besides the large cities mentioned there arc a hundred
smaller places upon the shores of the lakes which take
their water from them, and there are some other cities
which do not use lake water. Toledo, Ohio, finds it
cheaper and better to use Maumee River water than to
put in the expensive intake and appurtenances which
would be necessary to secure lake water beyond the
influence of local pollution.
In the smaller cities upon the lakes the mingling of the
sewage and water may be relatively just as important as
in the larger ones. They have less money to spend;
their intakes do not go out so far; their sewers are apt to
discharge at the nearest point, sometimes directly in front
of the water works intake; the water may be shallow,
and stirred by the wind to the bottom; and in short,
Menominee's sewage in Menominee's water may be
just as bad as Chicago's sewage in Chicago's water.
CHAPTER IV.
WATER SUPPLIES FROM RIVERS.
The following large cities in the United States take
their water supplies from large rivers:
Place.
Population
1900.
Water from
what river.
Drainage
area above
intake '
sq. miles.
Urban
population
above
intake
1900.
Urban pop-
ulation per
sq. mile.
Philadelphia .
1*293,697
Delaware .
8,186
242,788
3<y
Schuylkill
1,915
186,682
98
St. Louis , .
575,238
Mississippi
700,663
4,388,781
6
Pittsburgh . .
321,616
Allegheny
11,400
182,332
16
Monongahela
7,600
156,412
21
New Orleans .
287,104
Mississippi
1,261,084
9,157,348
7
Washington . .
278,718
Potomac .
11,476
79,563
7
Louisville . . .
204,731
Ohio . .
91,000
2,303,001
25
Minneapolis
202,718
Mississippi
19,585
21,961
I
Providence . .
175,597
Pawtuxet
203
Indianapolis . .
169,164
White . .
1,820
66,083
36
Kansas City, Mo.
163,752
Missouri .
426,893
653,667
2
Toledo ....
131,822
Maumee .
6,273
112,470
17
Allegheny . . .
129,896
Allegheny
11,400
182,332
16
Paterson . . .
105,171
Passaic .
773
17,205
22
St. Joseph . .
102,979
Missouri .
426,000
501,902
I
Omaha ....
102,555
Missouri .
322,500
87,554
0.3
In addition to these a very large number of smaller
cities and towns take their water from the rivers of the
country.
In large parts of the country the rivers are the only
32
1
SANITARY ASPECTS. 33
adequate available sources of supply, and they will always
so remain.
Sanitary Aspects of River Water Supplies. From an
hygienic standpoint the succession of cities and manufac-
turing establishments on the same river, and the combined
use of the river as a sewer and source of water supply is
most significant.
On some rivers, like the Merrimack, Hudson, Dela-
ware, Ohio, Missouri, and Mississippi, this succession is
particularly impressive, and, when the water has been
used in its raw or unpurified state, sickness and death
have resulted, and thousands of lives have been lost in
this way.
The relation of water supply to sickness and death has
been shown with force in many cities, notably at Lowell
and Lawrence, Massachusetts, at Albany, New York, at
Jersey City and Newark, New Jersey, and abroad at
London, Paris, Hamburg, Altona, BerUn, etc. Some of
these cities have since abandoned the objectionable sup-
plies. Others have installed purification works which
have removed the poisonous qualities of the river waters.
At Lowell a groimd water supply was secured to take
the place of the polluted river water; at Jersey City and
Newark new supplies from impounding reservoirs were
substituted; while Lawrence and Albany constructed
purification works.
Substitute supplies have also been proposed in a num-
ber of other large cities. In some cases such supplies
could be obtained, though often at greater expense than
can now be afforded; but in many or most cases the river
water is the only water that can be obtained in sufficient
34 WATER SUPPLIES FROM RIVERS.
amount. Where this is the case there is no alternative.
The river water must continue to be the source of
supply.
It is possible to purify sewage before discharging it
into rivers. If all the cities and towns purified their
sewage, and if all manufacturing establishments (which
sometimes contribute as much as the cities to the pollu-
tion of the streams) did the same, then the river waters
of the country would be less polluted, and would be
more desirable as sources of public water supply.
Some people believe that all sewage and wastes should
be so purified before being discharged, and that the rivers
should be so protected from pollution.
A few large cities, notably Worcester and Providence,
do partially purify their sewage, and many smaller ones
do so. But in very few cases has this been done to pre-
vent the pollution of a public water supply taken from
the stream below the sewer outlet. Sewage has usually
been purified only in those cases where a local nuisance
was created in the stream below the outfall, or at least
where such a nuisance was anticipated, rightly or wrongly,
in case crude discharge was permitted.
By local nuisance is meant the discoloration of the
water, the presence of floating substances objectionable
in appearance, the deposition of sewage mud on the be
of the stream, and the production of offensive odor
All of which make, or tend to make, the stream a^
its banks and neighborhood less desirable for bathi:
boating, navigation, business, residence, and, in sh
less useful to the public, and especially to those li\in
or often passing the locality.
SANITARY ASPECTS. 35
Now, whether or not a local nuisance is caused by the
discharge of sewage depends upon the relative amounts
of sewage and flowing water, and upon the rapidity of
current and the temperature, etc. These matters need
not be here discussed. It will suffice to state that there
are numerous cases where local nuisances are produced
which would amply justify the purification of the sewage
to prevent them, but that in other cases, and, in fact, in
a great majority of cases where sewage is discharged
into rivers, there does not result any local nuisance which
would justify, to prevent it, the expenditure of the money
necessary to purify the sewage, or, even if the work could
be done for it, of one-tenth of the required sum.
Where sewage is purified to prevent a local nuisance
in a stream from which a public water supply is taken
below, then certainly the purification is advantageous to
the quahtj of that supply; but this is the exceptional
case and not the common one. To set about cleaning
up the rivers of the country for the purpose of improxing
the quality of the public water supplies would involve
the purification of sewage from thousands of cities and
towns where that was the only reason for the purifica-
tion, or, in other words, where there was no local nui-
sance produced by the discharge of crude sewage.
To protect the water supply of Louisville, it would be
necessary to purify the sewage of Cincinnati, Pittsburgh,
and hundreds of smaller cities upon the Ohio River and
its tributaries. From the standpoint of local nuisance,
the purification of the sewage from a few of these cities
is already necessary, and, as time goes on and population
increases, it will be necessary to treat the sewage from
36 WATER SUPPLIES FROM RIVERS.
an ever increasing number of cities in this way; but the
fact must be fully recognized that the discharge of crude
sewage from the great majority of cities is not locally
objectionable in any way to justify the cost of sewage
purification.
Looking at the whole matter as one great engineering
problem, it is clearly and immistakably better to purify
the water i .ipplies taken from the rivers than to purify the
sewage before it is discharged into them.
It is very much cheaper to do it in this way. The
volume to be handled is less, and per million gallons the
cost of purifying water is much less than the cost of
purifying sewage.
It is also very much more effective to treat the water,
because the methods of water purification are more
efi&cient in stopping germs of disease than are the
methods of sewage purification.
It is also more effective, because all the water used
can be with certainty treated, while it is well known that
very few sewage purification works treat all the sewage
from the districts which they serve. There are storm
overflows; there is the street wash that may not pass
through the sewers; there are the thousand minor pollu-
tions that practically cannot be stopped, even though
the sewage is treated and all reasonable precaution taken
in connection with it.
It is, therefore, both cheaper and more effective to
purify the water, and to allow the sewage to be dis-
charged, without treatment, so far as there are not other
reasons for keeping it out of the rivers. It seems
imlikcly that a single case could be found where a given
TURBIDITY. 37
and reasonably sufficient expenditure of money wisely
made could do as much to improve the quality of a given
water supply when expended in purifying sewage above,
as could be secured from the same amouuc of money in
treating the water. Usually I believe that there would
be a wide ratio: that one dollar spent in purifying the
water would do as much as ten dollars spent in sewage
purification.
The water works man therefore must, and rightly
should, accept a certain amount of sewage pollution in
river water, and make the best of it. Taking it up in
this way he will master the situation by purifying the
water. Success in supplying good water cannot be
otherwise reached.
The general project of keeping all sewage out of rivers
is attractive, and it vdW always have its earnest advocates;
but it is not a practical proposition and it is not necessary.
It is not even desirable, when the greater good to be
secured by a given expenditure in other directions is taken
into accoimt. Although the public is ignorant of such
matters, still, in a general, indefinite sort of a way it does
even now understand some of the elements of the situa-
tion, and as time goes on it is bound to understand them
better.
Turbidity. After sanitary qualities there is no feature
of river water supplies of more general interest and
importance than the turbidity, or muddiness of the
water. All river waters are more or less turbid, but the
differences are very great indeed. They come principally
from differences in character of the catchment areas.
The Merrimack and Connecticut Rivers in New Eng-j
38 WATER SUPPLIES FROM RIVERS.
land, draining areas largely covered with glacial drift of
a sandy character, are but little subject to turbidity. As
an annual average they do not carry more than ten parts
per million of suspended matter. Usually they carry much
less than even this small amount; but once or twice in a
year there is a flood which washes away some of the
banks and carries along a considerable amount of silt, but
even this rapidly settles out when opportunity presents.
Of the same general character in this respect are the
waters of the Upper Hudson and of the rivers of Northern
New York, Michigan, Wisconsin, and Minnesota, in-
cluding the upper Mississippi, and also most of those of
northern New Jersey. Small streams rising near the
coast and in the sand hills back of it are also found here
and there all down the Atlantic coast which are not
greatly subject to turbidity. Some waters from moim-
tainous regions where the rocks are hard are also nearly
free from turbidity. Such streams are found near the
Pacific coast in the Sierra and coast ranges.
Speaking generally, the rest of the river waters of the
country are more turbid. Some of them, it is true, are
usually fairly clear, and are only subject to excessive tur-
bidity for short intervals in infrequent floods. Such are
the Delaware, the Allegheny, and some of the streams in
northern Ohio, Indiana, ::nd Illinois.
Farther south the turbidities run higher and also last
longer. The larger streams flowing to the Atlantic coast
south of the Delaware have very turbid periods and are
usually subject to very rapid fluctuation in turbidity. A
sudden storm may increase it a hundredfold in a few
hours. The Ohio River and its southern tributaries are
COLOR IN RIVER WATERS. 39
subject to large amounts of turbidity, and muddy water
sometimes flows in them continuously for much longer
periods than in the Atlantic coast streams.
The Missouri River carries the largest amount of sedi-
ment of any of the rivers largely used for water supply,
and as an annual average the amount runs as high as
1 200 or 1500 parts per million. In winter it falls to 200
parts or less, while in midsummer it rises for weeks, and
even months, to 5000 parts or more.
The Mississippi at Minneapolis is not much subject
to turbidity. As it flows south it becomes more turbid,
but even as far down as where the Missouri joins it, it is
comparatively a clear water stream. Below, it takes
more largely of the character of the Missouri. The
amount of sediment is less than in the Missouri, but the
Ohio and other tributaries bring to it a sediment that is
more finely divided and more difficult of removal, so
that for practical purposes the river at New Orleans is
as turbid as it is at St. Louis, even though the analytical
results show less suspended matter.
Color in River Waters. The color of water has already
been mentioned in connection with impounding reser-
voirs. The color referred to is the yellow color extracted
from dead leaves, from swamps, etc. This color is in
solution, and it is to be' sharply distinguished from the
turbidity which results from clay and other suspended
matter in the water. Turbidity is frequently spoken of
as color; and when the material composing it is colored,
as for instance, red clay, it is certainly correct to speak
of it in this way. But for the purpose of this discussion
color means only the yellow coloring matter that is in
40 WATER SUPPLIES FROM RIVERS.
solution. This is the meaning that is commonly adopted
by water analysts, and the distinction is necessary.
In a general way, colored waters are found in those
regions where turbidity is not found. But there are some
exceptions to this rule. The upper Delaware, among the
larger rivers, is comparatively free from color, and also
is usually free from turbidity. There are many smaller
streams of which this is also true. Spring water streams,
in sand hill districts, and mountain streams frequently
have these qualities. On the other hand, the upper
Mississippi is a highly colored stream, and it is also
occasionally moderately turbid.
In general, water flowing from swamps is colored, and
in a rough way the color of a river water is a measure of
the amount and character of the swampy area upon its
catchment area.
Many of the smaller streams of the north, from Maine
to Minnesota, are highly colored. So also are the smaller
streams from the swamps near the coast flowing to the
Atlantic all the way down the cof^st to Florida. Some
large rivers are colored to an extent which affects materi-
ally their value for water supply purposes, although they
are never as highly colored as some of the smaller streams.
Among the rivers colored so as to affect their value, and
which are important sources of pubHc water supply, may
be mentioned the Merrimack, Hudson, Black, Passaic.
Grand, and Mississippi Rivers. There are also many
others supplying smaller cities.
Turbidity and color render water less attractive, less
desirable, and less valuable for public supply. They can
be removed by purification methods, and their removal
COLOR IN RIVER WATERS. 41
is now generally demanded, although there are still many
cities supplied with water generally regarded as good but
which is subject to them in considerable amounts. This
is especially true of color.
It is only within the last few years that accurate
records of turbidity and color have been kept. Even
now they are kept by only a part of the water works that
are affected by them; and naturally even less is known
about the turbidities and colors of the waters of rivers
that are not used for water supplies. Our knowledge of
the general distribution and range of turbidity and color
is far short of what could be desired. It is being added
to rapidly, however.
CHAPTER V.
GROUND WATER SUPPLIES.
Water drawn from the ground by wells or taken from
springs is called ground water, and this source of supply
is a most important one.
It is easier in proportion to get a little groimd water
than to get a larger amoimt, and for this reason ground
water supplies are more generally available for, and better
adapted to, the needs of small places than of large cities.
If the water supplies of the country could be all counted
up, each plant counting for one regardless of its size, it
would be found that the groimd water supplies were
more numerous than those of any other kmd, probably
in fact more numerous than all the others put together.
But as the average size of the ground water supplies is
small, the total amoimt of water supplied from them
would be much smaller than that supplied from impound-
ing reservoirs, or from rivers.
In Europe ground water supplies have been secured
for many large cities. There are no corresponding de-.
velopments in America. The reasons for the greater
use of this method of supply in Europe are:
1st; Smaller quantity of water required per capita.
2d; More favorable geological conditions.
3d: More study given to the subject, and greater
efforts made to secure them, especially in Germany.
42
FROM SAND AND GRAVEL DEPOSITS. 43
Without discussing these points in detail it may be
said that few large American cities are situated where
there are sufficient beds of sand and gravel, or other
previous formations to yield water for their supply, such
as exist over a considerable part of central and northern
Europe, and which have been drawn upon most success-
fully by even the largest cities.
Ground Water from Sand and Gravel Deposits. Occa-
sionally there are locations where such supplies, com-
parable to the more important European supplies can be
secured in America. Of these none is more favorable
than that of the Brooklyn water works of the city of New
York. Of the total supply of 127,000,000 gallons daily,
78,000,000 gallons, or 62 per cent, is obtained from the
groimd, mostly from tubular wells driven in the coarse,
open sand and gravel. These wells are in groups, each
group being pumped by a pumping station, which
throws the water into a collecting conduit, which takes
it to other pumps, which finally raise it for the city service.
The ground water is not kept separate, but is mixed in
the conduit with the pond and reservoir waters, which
make up the balance of the supply.
Separating the works into so many small units, each
with its own pumping station, adds greatly to the cost
of securing the water, but either this or its equivalent
seems to be necessary.
Only so much water can be secured from a square
mile of ground. The amount depends upon the rain-
fall, upon the evaporation from the surface of the ground
and from the vegetation, and upon the amount of storage
in the pores of the soil. And all these matters may be
44 GROUND WATER SUPPLIES.
computed in much the same way that the yield of an
impounding reservoir can be calculated. The yield is
measured by the rainfall, in a dry year, less the evapo-
ration; and the available yield is either this amount, or
that part of it which can be maintained as a steady flow
throughout the year by the storage in the pores of the
earth. Most of the available yield is collected during
the winter when evaporation is slight, and the supply
must be maintained through the summer by the reserve
thus accumulated.
At Brooklyn the conditions for storage are most favor-
able, and it is estimated that 750,000 gallons per day can
be drawn from each square mile of catchment area.
I Water flows through sand only with some difficulty.
{From a given pumping station it is only possible to draw
the water for a limited distance. This distance depends
upon the depth and coarseness of the sand. The area
/that can be served by one pumping station is consider-
I ably extended by the use of wells at some distance from
each other, connected by pipe lines leading to the pumps.
But practically there is a limit, and the only way to
secure a large quantity of water is by the use of a number
of comparatively small pumping stations, separated so
as not to draw from the same territory. In Brooklyn,
to secure 78,000,000 gallons of ground water per day,
twenty-four separate pumping stations are used. From
one infiltration gallery 13,000,000 gallons per day are
obtained. Otherwise the greatest average quantity of
water from one station does not exceed 6,500,000 gal-
lons daily. And the average quantity from one station
is only about 3,000,000 gallons daily*
FROM SAND AND GRAVEL DEPOSITS. 45
The favorable conditions at Brooklyn extend over a
considerable area on Long Island, and also in southern
New Jersey. In this area there are many smaller ground
water supplies. Of these the one at Camden, N. J.,
deserves special mention. The water is lifted by com-
pressed air, from wells extending over a considerable
area and forwarded to one central pumping station. The
air is compressed at this station, and is carried to the
wells in wrought iron pipes. By this means an unusually
large amount of water is handled at one station. There
is an economy in labor, but the use of coal is not re-
duced, as the compressed air is not an efficient means
of transmitting power.
The compressed air method of pumping is extensively
used for raising ground water to the surface of the
ground. It is used both where the wells are far removed
from the pumping station, and where the water level in
the wells is too far below the pumps to permit of its being
taken directly by them.
In Camden (pop. 75,935), the wells are close to the
Delaware River, and the amount of water obtainable is
increased by taking river water over the surface of some
of the ground about the wells. This water filters through
the sand slowly and is well purified. This method
of adding to the yield of wells is used at some places
in Germany and France.
Memphis, Tenn. (pop. 102,320), is probably the
largest city in the United States suppUed entirely with
water drawn from sand and gravel deposits. In this case
the water-bearing area is several hundred feet below the
surface and is below a clay layer.
46 GROUND WATER SUPPLIES.
Lowell, Mass. (pop. 94,969), has had three stations
draining different areas of glacial drift, but at present
the whole supply is maintained from two of them. Of
these the one yielding the larger quantity of water is on
the bank of the Merrimack River.
Filter galleries, or excavations in sandy materials near
river banks, have been used in the past. At present tub-
ular wells are usually preferred. It makes no difference
with the quality of the water which is used. The wells
allow the water to be drawn at a lower level, and this
tends to the drainage of a greater area, thereby securing
a larger quantity of water at one station.
Formerly many towns and cities were supplied with
ground water from gravel deposits which are now sup-
plied with water from other sources. The change has
usually been made because the ground water works
were not able to supply the increasing quantities of water
required by rapidly growing populations. To a certain
point, limited by the area of collecting surface and storage
capacity in the sand, the quantity of water obtained can
be increased, but this limit is reached sooner or later.
When the supply is derived in part from infiltration
from a neighboring river, there is often or usually a grad-
ual decrease in the amount of water available. This is
because the pores in the filtering material become filled
with the sediment of the river water which enters them.
In some torrential streams the filtering surface is renewed
from time to time, but usually this does not occur, and
there is no way of renewing the source when its capacity
is reduced in this way..
Wells in Sandstone Rock. Wells in porous sandstone
•i
WELLS IN SANDSTONE ROCK. 47
rock are often used where such rock exists. The
Marshall, and Potsdam sandstones underlying parts
of Michigan, Illinois, Wisconsin, and Minnesota, are
used extensively for supplying towns and small cities.
Jackson, Mich. (pop. 25,180), is one of the largest cities
so supplied.
The method of driving the wells differs from that of
driv-ing wells in sand, but the collection, storage, and flow
of water are precisely the same. The cementing ma-
terial which binds what would otherwise be loose sand
into a solid rock often seems to offer but little resistance
to the flow of water, and the sandstone, for water supply
purposes, acts as so much sand would do.
Most of the sand deposits of the country are not prac-
tically available for water supply purposes because the
grains of sand are too small, and the flow of water through
them is too slow. It is only the coarse-grain sands that
are practically available. In the same way there is a
great difference in sandstones. Only the coarse-grained
ones yield water freely, and some of the most extensive
formations are not water bearing.
Water drawn from sandstone is always well filtered.
The amount of water which could be obtained from
sandstone formations in some parts of the country with
sufficiently extended works is very great indeed, and the
water is of the greatest value for small supplies. For
large supplies, the limited amount that can usually be
drawn regularly by one pumping station is a serious ob-
stacle. The multiplication of small, scattered pumping
stations may often involve a larger outlay than the cost
of securing good water in other ways.
48 GROUND WATER SUPPLIES.
It very rarely happens that over 3,000,000 gallons of
water per day are handled from one pumping station,
either from sand or from sandstone. The capacities of
by far the greater number of such sources will be fully
reached with much lower drafts, often with as little as
1,000,000 gallons per day, or even less.
Limestone Water. Bethlehem, Pa., is not a large city
but it is an old one, and it was one of the first in this
country to have a public water supply. This supply
was from a spring coming through a crevice in the
limestone rock. The spring is one of the outlets for the
drainage of a considerable area near the city and higher
than it. The underground flow of the water is not
through the porous rock, for limestone is not porous. It
is through fissures or passages. These are called caverns
if they are large enough and are accessible. Such fis-
sures or passages exist in most limestone formations.
They are the natural seams or cracks enlarged by the
gradual solution and removal of the rock by the passing
water. Limestone is the only common rock that is
soluble in this way, and, for water supply purposes, lime-
stone formations must be distinguished from all others.
As the crevices may be, and often are, continuous for
many miles, and as they are large enough so that large
quantities of water can flow through them, it often hap-
pens that quantities of water, many times greater than
are ever obtainable from sandstone, are to be secured
from limestone. On the other hand, as limestone is not
porous, except for the open passages, there is but little
storage in a limestone country. That is to say, there is
but little ability to hold the abundant winter flows to
LIMESTONE WATERS. 49
maintain the supply through summer droughts. The
diflFerence between limestone and sandstone in this
respect is striking. While much more water is frequently
available at one point in limestone, the amount is sub-
ject to greater fluctuations, and the supply may fall short
when most needed.
San Antonio, Texas (pop. 53,321), is supplied with
water from limestone springs flowing in great volume.
For a long time, until the city grew to be too large, the
flow was sufi&cient to furnish water power on a moderate
fall just below the springs, to pump the water required to
supply the city to an elevated reservoir.
Wells drilled in limestone rock, if they strike large
and extended passages, often yield water freely. Such
wells may drain the materiarover the limestone for miles.
If that material happens to be clayey or impervious, the
yield will be less.
Indianapolis was at one time supplied from wells in
limestone, and Winnipeg in Canada is still so supplied.
In both cases the amounts obtainable were too small to
allow continued dependence on these supplies.
Limestone waters are not well filtered. To a large
extent they are subject to pollution from the entrance of
whatever polluting materials there may be on the tribu-
■ tary areas. Paris, France, partially supplied with lime-
stone water, has been much troubled by such pollution.
The water was for many years believed to be pure, but
more recent investigations have made it clear that at
least a considerable part of the excessive amount of
typhoid fever long prevalent in the French capital has
been caused by this water.
so GROUND WATER SUPPLIES.
Vienna has been more fortunate, but this is because the
catchment area supplying the wonderful "Kaiser Brun-
nen," and the other limestone sources largely supplying
the city, are all in the high mountains, where there is
scarcely any population or pollution. For these sup-
plies the storage question is supplied in a most unusual
way, namely, by means of ice and snow. The high
mountains are snow-capped, and the melting snow in
summer replenishes the springs, so that the summer dis-
charges are greater than the winter ones.
In general, limestone supplies are of inferior sanitary
quality. Typhoid fever has been caused by their use rather
frequently. Such cases have been investigated repeatedly
and thoroughly in Germany, Switzerland, France, and
England, and less frequently in the United States.
Sandstones and limestones are the only rocks impor-
tant as sources of underground water. Artesian wells
are sometimes sunk in other rocks, and occasionally
water is secured. This happens where the well strikes
an open seam, which serves as a passageway for water
entering it from pervious overlying material. Wells of
this kind seldom yield enough water for public supplies,
even in small towns, though supplies for private resi-
dences, small hotels, and mills, are not infrequently
obtained in this way.
Hardness of Ground Waters. Ground waters are apt
to be hard; that is to say, they contain large amounts
of lime and magnesia in solution. This tends to make
them less desirable for public water supplies. Fre-
quently, however, this is not a controlling consideration,
although always an important one.
HARDNESS OF GROUND WATERS. 5 1
Two conditions must be present to make a groimd
water hard. First, the material through which the water
passes, or some of it, must contain the hardness-produc-
ing material, and second, the conditions must be favor-
able for dissolving it. The latter practically means that
carbonic acid must be present.
The waters from the gravels at Brooklyn and Camden
and Lowell are soft, because the gravels contain but
little lime, and that little is not in a soluble condition.
Sand and gravel free from lime are common in New
England, parts of New York and New Jersey, and
generally along the Atlantic coast to the southward.
On the other hand, the sands and gravels of central
New York, and westward to Minnesota and beyond,
contain lime in considerable quantities, and waters
drawn from them are hard.
Different waters drawn from lime-containing materials
vary greatly in hardness. Generally the hardness of the
water does not depend upon the amount of lime in
the material through which it has passed, but upon the
power of the water to dissolve the lime. If any lime
at all is present in form to be dissolved, there is pretty
sure to be enough of it to render the water extremely
hard if carbonic acid is present in the water to take
it up.
Rain water contains but little carbonic acid, and has
therefore but little power of dissolving lime, and so of
becoming hard while passing calcareous materials. The
principal source of the carbonic acid required to enable
the water to dissolve lime is the soil. The soil contains
organic matter in the shape of roots, humus, etc. Some
52 GROUND WATER SUPPLIES.
of these matters are decaying and becoming oxidized
with the formation of carbonic acid. The rain falls
on the soil, penetrates it, and becomes charged with
carbonic acid. Then it passes to the calcareous sand
or other material below, and lime from it is dissolved
to the extent of the dissolving power of the carbonic
acid.
The hardness of the water therefore depends more
upon the richness or fertility of the soil upon the catch-
ment area than upon the amount of lime in the various
materials through which the water flows, provided of
course that there is some substantial amount of lime to
be taken up where conditions permit.
The water supply of Vienna is for this reason compar-
atively soft, notwithstanding that it comes entirely from
limestone rocks. The gathering ground is barren and
sterile, and the water never gets the carbonic acid needed
to dissolve a large amount of lime. In a sand-hill region,
where the sand is calcareous, the ground water will be
only moderately hard, because of the barrenness of the
soil. With better soil, the water will be harder, until
with an extremely rich, fertile soil over limestone, as at
Winnipeg, Canada, water of the very greatest hardness
is found.
Iron in Ground Water. After hardness there is no
question of greater importance in considering the quality
of ground waters than the presence of iron. Iron is
very widely distributed, and practically all the sands,
gravels, soils, and rocks with which water comes in con-
tact, from the time it strikes the soil as rain water until it
emerges to the spring or well, contain it. Sometimes the
IRON IN GROUND WATER. 53
conditions are not such as to result in the solution of the
iron, but frequently an objectionable amount of it is
taken into solution.
When iron is present in water it supports the growth
of crenothrix, an organism which grows in the pipes and
which is extremely troublesome. And it further sepa-
rates, forming a red precipitate which is ofifensive in
appearance and is dirty in tanks and wherever the water
is stored. Water containing iron also discolors and
spoils linen and other fabrics washed in it.
The solution of iron from the soil is brought about by
organic matter. This takes oxygen away from the iron
of the soil, reducing it from the ferric to the ferrous
state. In the ferrous state the iron is soluble in water
containing carbonic acid, and trouble from iron is
always to be expected where there is an excess of
organic matter in the material through which the water
passes.
The organic matter may come with the water itself, in
case of seepage from a dirty and polluted river; or it may
be present in the soil. Rain water does not contain much
organic matter, but the soil on which it falls is usually rich
in it. In a well drained, pervious soil the oxygen from
the air circulates in the pores of the soil and furnishes
what is required by the organic matter. Iron will not
be dissolved under these conditions, even in presence of
large amounts of organic matter. But if the air supply
is cut oflF, as, for instance, in case the pores of the soil are
filled with water by flooding or saturation, the solution
of iron is sure to take place.
Iron can be removed from ground water by a suitable
54 GROUND WATER SUPPLIES.
method of purification, and such removal has made pos-
sible the utilization of many valuable sources of supply
that otherwise could not have been used.
The ground waters of northern Germany very com-
monly contain iron. Twenty years ago Berlin put down
many wells and works for securing ground water, the
conditions in the neighborhood of that city being excep-
tionally favorable. But after a short period of use the
wells were abandoned because of the iron in the water
which made the water objectionable. At that time it
was not known how to remove the iron. Afterward
methods of iron removal were discovered and used in
other German cities, and finally in the last years the old
Berlin well water supplies have been gradually brought
back into service and extended, but this time with the
complete artificial removal of the iron from the water.
And this water is gradually supplanting the filtered river
water which otherwise has been used to supply the city.
All these German iron-containing waters are from
deposits of siUcious sand, in a general way, similar to that
from which the Brooklyn, Lowell, and Camden suppUes
are obtained.
Of the American ground water supplies, a consider-
able proportion suffer from iron, and a number of works
for iron removal are in use, though not for the larger
suppUes. As far as known, the Camden supply has not
suffered from iron. At Lowell, the iron is more or less
troublesome. The Brooklyn wells are very variable,
according to location. Some are free from iron. Others
have so much that the unmixed water from individual
wells would not be usable. But when it is all mixed in
IRON IN GROUND WATER. 55
the conduit, including large amounts of surface water,
the iron is not present in large enough amounts to be very
troublesome. It is noticed, however, and is an unde-
sirable element in the supply.
Superior, Wis., Far Rockaway, N. Y., and Asbury
Park, N. J., are among the most important and best
known places in -the United States, where the iron, in
ground water supplies has compelled the construction
of works for its removal.
Manganese also occurs in ground waters occasionally.
Manganese is a metal similar in many ways to iron, and
is the basis of the "spiegeleisen,'' used in making steel.
It is less widely distributed in nature than iron. When
it is present in the soil it dissolves under the same con-
ditions that lead to the solution of iron. It is equally
troublesome to the users of the water, and is much more
difficult to remove by artificial purification.
Breslau, Germany, has suffered from manganese as
well as from iron, and part of the recently constructed
ground water supply works have been abandoned because
of it.
As far as known manganese has not been troublesome
in any very large public supply in America, but it has
proved most objectionable in a few small ones, and in
some mill supplies.
It is much more diflicult to test water for manganese
than for iron, and but few chemists have looked for it
adequately. It is therefore possible that full investi-
gation will show a wider distribution of manganese in
American waters than is now recognized, and that some
56 GROUND WATER SUPPLIES.
troubles with water, the causes of which are not now
understood, may be attributed to this metal.
Sea Water in Ground Water Supplies. Many impor-
tant supplies are drawn from wells near the ocean. The
Brooklyn supply is so located, also the Far Rockaway
supply, and the supplies for Staten Island and Asbury
Park, and many small places along the New Jersey coast.
The supplies of The Hague and Amsterdam in Holland
are also obtained close to the coast. In all these cases
the presence of sea water in the wells is an important
matter. In many cases trouble has already been experi-
enced. In others there would be trouble if care was not
exercised to prevent it.
The admixture of even a small proportion of sea
water renders the water hard and salty and undesirable
for domestic use. The magnesium chloride also ren-
ders such water unsuitable for use in boilers. The pas-
sage of sea water through the sand between the sea and
the wells does not remove the salt of the sea water, or
even reduce it in the sUghtest degree.
In most of the supplies above mentioned the fresh
water resulting from the rainfall upon the sandy areas
near the coast naturally reaches the sea through the
sand below the water lev6l. Its discharge accounts
for the springs and quicksands often noticed on the
beach at low tide. Little or none of this water naturally
comes to the surface of the ground before reaching the
sea.
It is a difficult matter to draw to wells or galleries all
the fresh water that would otherwise flow to the ocean.
SEA WATER IN GROUND WATER SUPPLIES. 57
without at the same time drawing some salt water to the
wells. In fact, it is not possible to do this perfectly. It
is an interesting ancl difficult problem to so arrange and
operate the works as to get the maximum quantity of
fresh water without drawing sea water.
The problem is complicated by a fairly strong ten-
dency, due to the difference in specific gravity, for
sea water to flow back under the land in the sand
below the surface, when the water level at a distance .
back from the shore is lowered by drawing upon the
wells; and this underflow of salt water may take place
while there is still a surface flow of fresh water to the
ocean.
When sea water passes back under the wells in this
manner it is sure to become mixed with the fresh water
above it in the wells sooner or later. The process of mix-
ing is constantly taking place from the first moment that
sea water begins to flow into the land, and by the time
that sea water is first detected in the wells, large amounts
of sea water may be in the sand below them, and it may
then be a slow, hard process to operate the wells so as to
avoid drawing sea water.
It is clear that for a time an amount of fresh water
largely in excess of the yield that can be permanently
maintained can be drawn from such wells, the excess
amount being taken from the sand, and its space being
gradually taken by salt water. For this reason the
amount of water which can be permanently maintained
from such works is much more difficult to determine, and
in fact can only be determined by experience extending
5 8 GROUND WATER SUPPLIES.
over a far longer period than is required to establish the
yield of wells not so situated.
This sea water question has been more thoroughly and
scientifically studied in Holland than elsewhere. The
Dutch literature upon this subject is most important, and
many of the methods of studying conditions and of regu-
lating the supply that are there used may be adopted
elsewhere with advantage.
CHAPTER VI. ,
ON THE ACTION OF WATER ON IRON PIPES
AND THE EFFECT THEREOF ON THE
QUALITY OF THE WATER.
It is well known that nearly all waters attack iron pipes,
corroding them and forming tubercles on the inner sur-
face. The rates at which this corrosion and tubercu-
lation take place with different waters and different
kinds of pipe have been studied by many engineers at
length. It has been studied almost entirely from the
point of view of the reduction of carrying capacity of the
pipe, and hardly at all from the standpoint of the effect
upon the quality of the water. The latter seems to be
a matter of considerable importance, however.
The way that the process of tubcrculation goes for-
ward seems to be something like this : The water flowing,
at times slowly, and carrying matters in suspension, de-
posits some of these suspended matters on the lower half
of the pipe. This deposit usually contains a consider-
able amount of organic matter.
The iron pipe is coated with tar or asphalt. If this
coating were perfect and complete, the deposit would not
come in contact with the iron at any point. But there
arc always blow-holes or other minute openings in the
coating, and it is through these that the iron is first
reached.
59
6o ACTION OF WATER ON IRON PIPES.
The organic matters in the deposit over the iron are in
a state of decomposition; that is to say, they are rotting.
Yhis resuhs in the generation of carbonic acid. The
carbonic acid acts on the iron through the openings in
the pipe coating. It takes some of this iron into solution
as ferrous carbonate. The soluble ferrous carbonate
diflFuscs through the water, penetrating the deposit under
which it is formed, and reaching the upper surface of it,
where it comes in contact with the water flowing in the
pipe. A part of the iron mingles with the water in the
pipe and goes forward with it. Another part, becoming
oxidized by the oxygen in the flowing water, is trans-
formed to the insoluble ferric condition and remains at
the surface of the deposit.
The iron precipitated in this way acts as a coagulant.
It coagulates some of the organic matter in the flowing
water at the point where the iron is precipitated. It
binds the organic matter so precipitated, and that
previously deposited, into a firm, compact, but porous
mass, and this mass is the beginning of a tubercle.
The organic matter precipitated by the iron at the
surface of the tubercle is so much fuel added to the flame
of decomposition, and the carbonic acid resulting from
it leads to the solution of further quantities of iron. In
this way the process becomes a continuous one.
The circulation of the Uquid through the tubercles,
taking the carbonic acid to the iron and bringing the iron
to the surface, is very slow, and many years may elapse
before the tubercle reaches the height of an inch.
Tuberculation is practically universal in cast iron
water pipes, but some waters cause the action to go for-
TUBERCULATION. 6t
ward much more rapidly than others. Tuberculation
starts much more freely, and progresses more rapidly,
in waters from rivers or reservoirs containing suspended
organic matters. It is less troublesome with filtered
waters and with lake waters relatively free from such
suspended matters. Pipes carrying river waters con-
taining much inorganic sediment, that is to say, clay and
silt, and having but little organic sediment, are less likely
to become tuberculated than those carrying waters with
organic sediment.
The diflference between the action of raw water and
filtered water upon pipes is very striking in the piping
about filter plants. The tubercles in the raw water pipes
are found to be much more numerous and larger than
those in the filtered water pipes.
The character of the tar or asphalt pipe coating also
has a great deal to do with tuberculation. The asphalt
put on sheet steel pipes seems to protect the metal more
thoroughly than the ordinary tar coating used for cast
iron pipes.
The cement lined pipes, extensively used years ago,
and now abandoned in water works practice because of
defects in other particulars, were not subject to tubercu-
lation, and had this distinct advantage over the cast iron
pipes which have displaced them.
The eCFect of tuberculation in increasing the frictional
resistance of water in pipes, or, what is the same thing, of
decreasing the flow through them, is well known. It is
common to find that twice as much head is required to
carry a given quantity of water through a pipe after
twenty years of use as when the pipe was new.
62 ACTION OF WATER ON IRON PIPES.
Pipe scrapers have been sometimes used to remove
tubercles. They consist of appliances driven by the
water pressure through the pipes with arrangements to
scrape oflF the tubercles. Scraping in this way has the
eCFect of restoring to a considerable extent the original
carrying capacity of the pipe. The process, to remain
eCFective, must be repeated at intervals, and when so re-
peated it has the efifect of removing a large part of the
tar coating and leaving the iron of the pipe exposed to the
action of the water to a much greater extent than would
have been the case without scraping.
The iron that is oxidized and dissolved as a result of
the process of tuberculation is, in considerable part, pre-
cipitated at the surface of the tubercles, and it forms the
cementing material which makes them possible. But
only a part of the iron is thus precipitated; the rest goes
forward with the flowing water. At first it is in a state
of solution, but the dissolved oxygen in the water oxi-
dizes it slowly to the ferric or insoluble state.
If the water contains much organic matter in solution
this may prevent the precipitation of the iron. In this
case it increases the color of the water. It is able to do
this only where the amount of iron in proportion to the
organic matter is comparatively small. This is usually
the case with dirty river and reservoir waters. If there
is not sufficient organic matter in the water to hold the
iron in solution, it will separate out after oxidation and
'Will deposit where the flow in the pipes is slow. This is
usually the case with filtered water and other waters of
organic purity.
That part of the water which goes through the water-
PRECIPITATION OF IRON 63
backs of the kitchen stoves to the hot- water tanks is par-
ticularly likely to have its iron separated, and the iron so
separated usually accumulates on the bottoms of the hot-
water tanks. The iron separating from the water in
this way is not likely to be drawn at all times. It is far
more likely to accumulate in pipes and tanks for days
or even for weeks, until sometime, with an unusually
rapid draft of water or other disturbance, perhaps on
washing-day, the iron which has accumulated for days
or weeks is all flushed out in a limited quantity of
water. Then the superintendent of the water works
hears from it.
This intermittent appearance of iron is one of the
characteristic features of iron troubles from ground
water, and the presence of iron is much more objection-
able to the takers of the water than it would be if it was
more imiformly distributed through the water.
The solution and subsequent precipitation of iron in
this way seems to be more or less universal in connection
with iron water pipes. The tendency of this action is
to make a surface water behave like a ground water
naturally containing iron, and all the disagreeable
features of an iron-containing ground water may be
produced in greater or less degree as a result of these
actions.
Where water is taken from a source that is recognized
to be dirty, as, for instance, from a turbid river or from a
reservoir with vegetable growths, the public is pretty
sure to take these phenomena as representing a part of
the natural dirtiness of the source. There are cases
where the imcleanness popularly attributed to the water
64 ACTION OF WATER ON IRON PIPES.
of the source is really attributable in greater measure to
the iron taken up from the pipes.
For this reason it seldom happens that the action of
the iron pipes in increasing the dirty appearance of the
water is recognized as long as the source of supply has a
bad reputation. When a filter plant is installed, or clean
water from a new source is secured in place of a dirty
one, then the effect of the iron commences to be noticed
and to receive serious attention. It is found that water
leaving a filter plant or entering the pipes from a new
reservoir, is bright, colorless, and free from iron. As
drawn from the taps to the consumers it is discolored
and comes out a milky yellow or reddish, according to
the amount of iron present. This color comes intermit-
tently, and between the dirty spells there arc times when
clean water is drawn. The people get used to the
appearance of clean water, and quickly notice the differ-
ence when the iron comes, and they are troubled by it.
Often they believe that the filter has gone wrong, or some
unreported source of pollution is reaching the water.
Sometimes the matter is aggravated by a softening by
chemical action and loosening of old deposits in the
pipes which follows a change in the character of the
water supply. When this is the case, repeated and ade-
quate flushings of the pipe will considerably improve
the situation.
To make flushing effective it is necessary to shut off
all side pipes and open the hydrants at the end of each
line of pipe, so as to produce through that line for a few
minutes a velocity many times greater than any that is
possible in ordinary use.
FLUSHING PIPES. 6$
Flushing must be done in tliis way to be effective,
and opening hydrants here and there throughout a city,
without closing the gates necessary to concentrate the
flow, simply has the effect of stirring up the old deposits
in the pipe, and of mixing them with the water, and of
producing unnecessarily bad water without effectively
removing the source of trouble.
This deterioration of water as a result of contact with
iron 'pipes, and especially of old pipes containing large
numbers of growing tubercles, is one of the most trouble-
some ones in connection with securing clean waters and
of supplying them through pipes long used for carrying
dirty water.
The troubles resulting from it are important, even
though not of equal importance to sanitary quality or to
turbidity and color. Water is never less wholesome
because of iron, but it is less attractive in appearance,
and the difference is clearly noticed by the public.
The tubercles that grow in water pipes are very good
friends to the men who sell spring water. They also do
a great deal to make possible the business of supplying
domestic filters.
Domestic filters are not in general a very sure means
of removing disease-producing qualities from polluted
waters. There are too many uncertainties connected
with their operation to make them reliable in this
respect. But the iron that comes from the pipes is
very easily removed by such filters, and good domestic
filters furnish the most convenient and satisfactory means
of removing such deposits from water that is otherwise
good.
66 ACTION OF WATER ON IRON PIPES.
Probably if new pipes should be provided in place of
the old ones, when clean water is secured at the source;
and if better coatings could be used, relatively little trou-
ble would be experienced from iron. But the old water
pipes are in use, and they represent large investments and
cannot be changed for a matter of secondary importance.
It is to be hoped that a study of this subject and a
recognition of its importance will result in time in the
use of better pipe-coatings, or possibly in the use of pipes
presenting to the water some surface which is not subject
to tuberculation.
In the meantime, managing the situation by flushing
out such old deposits as can be flushed out, by explain-
ing the action of the tubercles to those citizens who
are sure that the water is bad when it is only tempora-
rily discolored, and generally keeping the public good-
natured, calls for the greatest skill and tact on the part
of the water works superintendent.
CHAPTER VII.
DEVELOPMENT OF WATER PURIFICATION
IN AMERICA.
The filtration of river waters to remove sediment and
turbidity and other impurities has been practised in
Europe for many years. The first serious American
effort in this direction was made by the city of St. Louis
in 1866, when the late J. P. Kirkwood, a civil engineer,
was sent to Europe with instructions to study the art
and apply it to St. Louis.
Mr. Kirkwood made a report upon this subject, and
a general plan for works for St. Louis based upon this
study. This report was most remarkable for the in-
sight shown into the conditions of success with European
waters, and it will always remain as a singularly accu-
rate statement of the conditions of the art as they existed
at that time.
Kirkwood's plan for filtering the St. Louis water
was not adopted. Possibly the cost was too great and
the benefits of purification too little xmderstood- at that
time; but there is some reason for supposing that tests
made on a small scale, the results of which were not
made public, served to show the inadequacy of the pro-
posed plan. However that may be, we now know that
the plan would not have given success, and that no plan
67
68 WATER PURIFICATION IN AMERICA.
based on European experience could have done so.
For among the filters of Europe there was not one
that received water resembling even remotely the Mis-
sissippi River at St. Louis, or that was capable of
treating such water.
Although Kirkwood's design for St. Louis was never
carried out, several filters were built by other cities as a
result of his work and report. From his plans a filter
was built for Poughkeepsie, N. Y. There the conditions
were sufficiently like those of European filters; and the
plant was the first, and by far the most successful, of the
early water purification plants in this country. After-
ward a number of small but successful plants were built
upon similar lines. Among them were the filters at Hud-
son and at West Point, N. Y. (both near Poughkeepsie),
and at St. Johnsbury, Vt.
In other cases success was not attained. Lowell,
Columbus, Toledo, and other cities also copied the Pough-
keepsie filters more or less closely but without corres-
ponding success. These failures were no doubt due in
some cases to the failure to provide adequate filtering
area, and to modifications of the design which did not
prove to be beneficial. And in other cases they were due,
or partly due, to the fact that the water carried more
suspended matter, and this affected the process to such
an extent that the general method was not applicable.
Soon after this the late Professor William Ripley
Nichols of Boston became interested in filtration. He
made experiments with it, talked of its apf Ucation to the
particular problems with which he had to do, and wrote
an uncommonly interesting report upon the subject of
mSTORICAL. 69
water purification based, like Kirkwood's, upon Euro-
pean experience.
This report led to an experimental trial by the late
A. Fteley, then engineer of the Boston water works. Other
trials were made at Louisville and elsewhere. These
trials, on the whole, were not encouraging, and did not
lead to practical applications of the method.
About 1884 the beginnings of a new method of filtra-
tion, destined to play a large part in water purification,
made their appearance. The process was patented by
the late J. W; Hyatt, and the late Professor Albert R.
Leeds was largely interested in the early development
of the invention.
The essential and characteristic features of this method
were the addition of a coagulant or chemical precipi-
tant to the water, and afterward passing it through a
sand layer so arranged that it could be mechanically
washed by a reverse current of water, aided some-
times by other appliances. These features are char-
acteristic, and have been the distinctive features of
mechanical filtration, as it . is called, to the present
day.
This method met with some successes, and in the
decade that followed quite a number of plants were in-
stalled. These were divided between supplies for small
cities, and supplies for paper mills. Paper mills require
large quantities of clean water, and they have been among
the earliest and best patrons of those who had methods
of purifying water.
The Massachusetts State Board of Health commenced
to investigate the purification of sewage and water in
70 WATER PURIFICATION IN AMERICA.
1887. At first the purification of sewage received most
attention, but about 1890 the study of water purification
was taken up energetically. And this experimental
work did a great deal to develop the art of water purifi-
cation in America.
In carrying out these investigations Merrimack River
water only was used. This water, which was used by
the city of Lawrence at the time, contained a great deal
of sewage, and caused much typhoid fever among those
who used it. It was also somewhat colored, but was
not subject to much turbidity. It was in a general way
much the same kind of water that had been successfully
filtered in Europe for the supply of such cities as London,
Berlin, etc.
These experiments were carried out at Lawrence,
under the direction of Mr. Hiram F. Mills, with at first
the writer, and afterward Mr. George W. Fuller, and still
later Mr. H. W. Clark, in direct charge, and with the ad-
vice of the late Professor Thomas M. Drown, and of Pro-
fessor William T. Sedgwick. They served to determine
in a practical way the nature of the processes that were
investigated, and to show the conditions of success with
them as far as they could be determined by small experi-
ments; and the results obtained, which were most promis-
ing and were duly published, served to interest many
people in water purification.
As a result of these experiments the city of Lawrence
built a sand filter to purify its water supply. This was
designed by Mr. Mills, following in a general way, but
not in detail, European precedent, for it was based
largely upon the results of the tests made, and in many
THE LAWRENCE FILTER. 7 1
ways it was quite diflferent from any previous construc-
tion. This filter was put in service in 1893.
The Lawrence fiUer was the first filter built in America
for the express purpose of reducing the death rate of the
population supplied, and it accomplished this purpose
in a most striking manner. Comparing the five years
after it was in service, with five years before it was in
use, there was a reduction of 79 per cent in the typhoid
fever death rate, which had been excessive for many
years. No less remarkable than this was the reduction
in the general death rate from all causes of 10 per cent,
namely from 22.4 to 19.9 per thousand living.
Following directly the success of the Lawrence filter,
a number of other filters were constructed more or less
like it, but none of them supplying as large a city as
Lawrence.
Up to the year 1893 but little progress had been made
in understanding the process of mechanical filtration,
although many plants had been installed, mostly in the
smaller cities and towns and in paper mills. The details
of construction and operation had been developed to a
considerable extent, but there was no adequate knowl-
edge of what could be done in securing pure water, or
how it could best be accomplished.
In that year Mr. Edmund B. Weston made some tests
for the city of Providence, which indicated that very good
work could be done by mechanical filters in purifying a
sewage-polluted water. These tests were by no means
all that could be desired, but they were important as
being the first carefully conducted tests with that kind
of filtration.
72 WATER PURIFICATION IN AMERICA.
Meanwhile, the mechanical filters installed, though
often giving relatively good service, were not by any
means doing so imiformly. The conditions of success
with them certainly were not understood. While excel-
lent results were occasionally reached, the average work
was at best mediocre, and there were conspicuous cases
of failure to accomplish the desired results.
The practical and scientific basis for mechanical fil-
tration may be said to date from the Louisville experi-
ments of 1895-97. These were made under the direction
of Mr. Charles Hermany, assisted by Mr. George W.
Fuller, acting for the Louisville Water Company, and
by several companies interested in the construction of
mechanical filters.
These experiments were made upon the Ohio River
water, and this water was radically different in quality
from the Merrimack River water which had been experi-
mented upon at Lawrence, as well as from all the waters
with which practical experience had been had in Europe.
The difference was principally in the matters carried
in suspension, or in the turbidity. The Ohio River
water carried varying amounts, and at times very large
amounts, of clay in suspension. Some of the clay par-
ticles are much smaller in size than the bacteria, the
smallest organisms, the removal of which has been
regarded as important. So finely divided is some of this
clay that it will hardly settle from the water at all.
The removal of this clay is important and necessary
on its own account, for no water can be considered ade-
quately purified and satisfactory for a public water sup-
ply while it contains any appreciable turbidity of this kind.
THE LOUISVILLE EXPERIMENTS. 73
Clay is also most important because when it is not re-
moved its presence exerts an influence on many other
things. Substances which would be readily removed by
a given treatment in the absence of clay particles, may
fail to respond to the treatment in the presence of such
particles, and a treatment otherwise successful may fail
when applied to a water containing them.
Now the Louisville experiments were the first to deal
\vith this question of clay particles in a comprehensive
way. The filtration proposed for St. Louis by Kirk-
wood, the filtration practiced in Europe, and the filtration
studied at Lawrence were hopelessly inadequate for this
business. The mechanical filters then in use in the
United States, and those selected and designed for these
tests were also inadequate, although they did embody to
a large extent the ideas that were to prove successful, and
were able, even at the outset, to accomplish a great deal.
As the tests progressed and the weaknesses of the vari-
ous devices became apparent, modifications weje made,
and in this way at Louisville the first thoroughly success-
ful method of treatment for this kind of water was reached.
The Louisville experiments brought mechanical filtra-
tion to a point where it was able to deal in an eflScient
and practical manner with many of the most diflScult of
American waters.
While the experiments were in progress at Louisville,
others were undertaken by the city of Pittsburgh, and
Cincinnati soon followed. Experiments were also made
at Washington, at Superior, and at New Orleans, and
elsewhere. And as a result of these, and the practical
experiences with other waters by the men having to do
74 WATER PURIFICATION IN AMERICA.
with them, and by a free exchange of the resuhs of this
experience between the different workers, data were
rapidly collected as to the characters of different waters,
and as to the ways in which they responded to different
treatments; and in this way a basis was reached for lay-
ing out methods of treatment capable of purifying a great
range of waters.
Now the range in the qualities of American waters is
much greater than the range in the qualities of European
waters. The excess of clay which has already been
mentioned is a controlling element in a considerable
portion of American river supplies.
With impounding reservoir supplies also there is a
difference almost as important, due to the higher sum-
mer temperatures and the growth of organisms, giving
rise to more seriously objectionable tastes and odors.
Such growths are not often troublesome under European
conditions.
Although the purification of water for the purpose of
removing tastes and odors is highly important, it has
received less study than the removal of clay. Never-
theless, something has been done with it. More study
has been given to preventive measures than to corrective
ones, although there are strong reasons for believing at
this time that the latter are more effective.
The city of Reading, Pa., made some experiments in
1897, in this direction, and since that time plants based
on the experimental results have been put in successful
operation for cleaning the water from two impounding
reservoirs, which were subject to algae growths, and
objectionable tastes and odors resulting therefrom.
TASTES AND ODORS. 7S
The Ludlow Reservoir at Springfield, Mass., was one
of the most notorious reservoirs for its tastes and odors.
The city of Springfield and the State Board of Health
made continued and elaborate experiments upon the
treatment of this water, from 1900 to 1903. These experi-
ments showed that the water could be successfully
treated, though with rather elaborate appliances and at
considerable cost.
Afterwards, in 1906, works for the purification of this
water were installed. These works differed somewhat
from anything that had been tested during the previous
experiments, being simpler and cheaper. Only a par-
tial purification was predicted and expected, but thus
far the results have exceeded expectations.
One of the most important of recent developments
in water purification has been the consideration of a par-
tial softening of river waters in connection with the
other processes necessary for their purification. The
idea of the possibility of doing this is very old. Wan-
klyn's "Water Analysis," published in London in 1868,
spoke at length of the possibility of doing this; but there
were practical difficulties, and the process was not actu-
ally used at any place, and it has only been since about
1903 that the process has been taken up in a way to re-
move the difficulties.
The development seems to have come about in this
way. The coagulant most commonly used in mechan-
ical filtration is sulphate of alumina or crude alum.
Now, sulphate of iron, or copperas, is cheaper, and
under some conditions fully as efficient as sulphate of
alumina as a coagulant. With the iron it is necessary
76 WATER PURIFICATION IN AMERICA.
to use lime, as without it precipitation is not suflSciently
rapid and complete. Only a little lime, comparatively,
is needed to throw down the iron. A considerably
larger quantity will also throw down some of the lime
naturally present in the water, together with the lime
that is added. This is the old and well known Clark
process for softening water, which is the basis of all
water-softening methods.
In 1903, the iron and lime process of treating water
was applied to the Mississippi River water supplied to
St. Louis. In this case the water, after the chemical
treatment, passed through settling basins but was not
filtered. At Quincy, 111., Lorain, Ohio, and other places
it was applied as a preliminary to filtration. And it was
soon found that when the amount of lime was increased,
accidentally or otherwise, the resulting efiluent was
often softer than the river water. And when this was
found it naturally led to the regular use of more lime and
perhaps of less iron. In this way a substantial amount
of softening was effected, at St. Louis and elsewhere, by
the iron and lime process.
The matter was investigated by an exhaustive series
of experiments at Columbus, Ohio, and the process was
developed with a view to a combined coagulation and
softening treatment prior to filtration. Works are now
being built on this basis to treat the Columbus water
with every prospect of success.
The indications are that the use of partial softening
brought about in this way will not greatly increase the
cost over that of the treatments otherwise necessary for
purification. It is even possible that with some river
METHODS OF COAGULATION. JJ
waters the process may be actually cheapened. If this
result IS secured it will be by making use of the magnesia
of the water to do a part of the work otherwise accom-
plished by alumina or iron. This will not always be
possible, but even when it is not, the advantage of soft
water to a city is so great that large expenditures can
well be made to secure it where the natural supply is hard.
While these advances have been made in the knowl-
edge of the processes of purification, and of the means of
carrying them out with success, an almost equal advance
has been made in the materials of construction of
mechanical filters and in their detailed arrangements.
The Hyatt patent, the underlying patent on mechan-
ical filters, expired in February, 1901. After that the
field was open. All other patents related to details; and
no one of them, nor even any combination of them,
could serve to control the field of filter construction.
From that day rapid advances were made. The de-
signs for the Louisville filters, which appeared in 1900,
were important as marking the beginning of a rapid ad-
vance. Reinforced concrete was substituted for the wood
and iron constructions previously used. The Little Falls
filters, treating the supply of the East Jersey Water Com-
pany, were put in service in September, 1902, and were
the first filters to be actually used on the newer lines.
These filters were also equipped with appliances for the
better and more certain control of coagulants and were
far better in other ways than any before constructed.
The use of larger coagulating basins to allow the
chemical changes to become complete before the water
passed to the filters was early introduced at a number of
78 WATER PURIFICATION IN AMERICA.
■
Missouri River points, especially at the works owned by
the American Water Works and Guarantee Company, at
East St. Louis, 111., and at St. Joseph, Mo.
The use of cement blocks for the bottoms of the filters,
containing the necessary channels for the efHuent and
wash water, in place of the metal structures previously
used, was introduced at the filters of the Hackensack
Water Company, built in 1904, and is also used with
modifications at Columbus, New Orleans, and elsewhere.
While these rapid and revolutionary developments in
mechanical filters have been taking place, sand filters,
following European precedent, have been installed in
many places where the conditions have been suitable and
in a few places where they were not, and developments
with them also have taken place.
Following the Lawrence filter, the first large installa-
tion was at Albany, put in service in 1899. These filters
were covered by masonry vaulting as a protection from
frost, which had interfered more or less with the winter
operation at Poughkeepsie and at Lawrence. Such cov-
ers had long been used in Germany for the same purpose,
and also at a few small American plants.
The Albany filters received water from the Hudson
River a few miles below the outlets of the Troy sewers.
The death rate in Albany was reduced by the use of the
filters as much as it has been at Lawrence.
At Philadelphia the construction of covered sand filters
was started in 1900, but the work has gone so slowly that
only parts of the works are in service at the present time.
At Washington the construction of covered sand filters
was authorized in 1902, and the plant was put in service
SAND FILTERS. 79
in 1905. In this case there has been no marked reduc-
tion in the death rate. The reason for this has been
made clear by extended investigations. The Potomac
River water used for supplying the city, after passing
through the settling basins, which held a week's supply,
and in which much bacterial purification took place, was
not the principal source of typhoid fever in Washington
nor an important cause of other water-borne diseases.
The. amount of sewage entering the Potomac above
the intake is only a small fraction of the amounts entering
the Merrimack above Lawrence and the Hudson above
Albany.
Providence installed a sand filtration plant, which was
put in service in 1905. Denver is mainly supplied by
water from sand filters, in service since 1902. Pittsburgh
is now building an extensive plant with covered filters
which will soon be in service.
Among the improvements in sand filters are the devel-
opments of methods of washing and preparing filter
sand, and of cheaply remo\ing and cleaning it after it
has become dirty from use, and of replacing it.
The first of these improvements has made it possible
to secure at moderate expense a filter sand of the best
quality in places where otherwise the use of filters of
this type would have been difficult. The second has
resulted in a great reduction in the cost of filtration. For
example, the cost of labor for removing, washing, and
replacing sand at Washington is about $0.60 per million
gallons, as compared 'with about $6.00 at Lawrence in
the early days before labor-saving devices were installed.
8o
WATER PURIFICATION IN AMERICA.
Partial List of Places in the United States where Fil-
ters ARE AT Present in Use or Under Constructi6n.
Mechanical Filters.
Place.
Cincinnati/ Ohio
New Orleans,* La
East Jersey Water Company
Hackensack Water Company
Louisville/ Ky
Toledo/ Ohio
Columbus/ Ohio
St. Joseph, Mo
Atlanta, Ga
Charleston, S. C
^nsas City, Kan.
Harrisburg, Penn. ,
Norfolk, Va. . . .
Youngstown, Ohio
Binghamton, N. Y.
Augusta, Ga. . .
Binningham, Ala.
Little Rock, Ark.
Terre Haute, Ind.
Dubuque, Iowa .
Quincy, 111. . .
Elmira, N. Y. .
Davenport, Iowa
Chester, Penn. .
York, Penn. . .
Knoxville, Tenn. .
Chattanooga, Tenn.
East St. Louis, HI.
Newcastle, Penn. .
Oshkosh, Wis. . .
Lexington, Ky. . .
Joplin, Mo. . . .
Cedar Rapids, Iowa
Population, igoo.
325»902
287,104
250,000
225,000
204,731
131,822
125,560
102,979
89,872
55i8o7
51,418
50,167
46,624
44,885
39,647
39,441
38,415
38,307
36,673
36,297
36,252
35,672
35,254
33,988
33,708
32,637
30,154
29,655
28,339
28,284
26,369
26,023
25,656
Capacity of
Filters in gallons
per day.
112,000,000
44,000,000
32,000,000
24,000,000
37,500,000
20,000,000
30,000,000
11,000,000
6,000,000
5,000,000
6,500,000
12,000,000
8,000,000
10,000,000
8,000,000
6,000,000
• • • •
5,500,000
9,000,000
4,000,000
7,000,000
7,000,000
4,000,000
4,000,000
4,500,000
9,000,000
11,000,000
4,000,000
2,000,000
3,500,000
• . . .
2,500,000
And fully 125 smaller places.
1 BaiUUai.
FILTERS IN USE.
8l
Sand Filters.
Place.
Philadelphia/ Penn.
Pittsburgh/ Penn. .
Washington, D. C.
Providence, R. I. .
Indianapolis, Ind. .
Denver, Col
New Haven, Conn, (in part)
Albany, N. Y
Reading, Penn. (in part) . .
Lawrence, Mass. . . .
Yonkers, N. Y. (in part)
Superior, Wis
Poughkeepsie, N. Y.
Population, xqoo.
1,293,697
321,616
278,718
175,597
169,164
133,859
108,027
94,151
78,961
62,559
47,931
31,091
24,029
Caps^ty of
filters in gallons
per day.
420,000,000
100,000,000
87,000,000
24,000,000
24,000,000
30,000,000
15,000,000
1 7,000,000
5,750,000
5,000,000
7,500,000
5,000,000
3,000,000
And fully 25 smaller places.
I Building.
CHAPTER Vni.
ON THE NATURE OF THE METHODS OF
PURIFYING WATER.
The general natures of these methods are elsewhere
noted in connection with the descriptions of different
kinds of water that require treatment. A brief state-
ment of the natures of the various processes at this point
may be helpful, even though some of the matter is
repeated.
The processes of water purification may be briefly
classified as follows:
I. Mechanical Separation:
By gravity — Sedimentation.
By screening — Screens, scrubbers, filters.
By adhesion — Scrubbers, filters.
11. Coagulation:
By chemical treatment resulting in drawing matters
together into groups, thereby making them more
susceptible to removal by mechanical separation, but
without any significant chemical change in the water.
in. Chemical Purification:
Softening — by the use of lime, etc.
Iron removal.
Neutralization of objectionable acids, etc.
IV. Poisoning Processes:
Ozone.
Sulphate of copper, etc.
82
PROCESSES OF PURIFICATION. 83
The object of these processes is to poison and kill objec-
tionable organisms, without at the same time adding
substances objectionable or poisonous to the users
of the water.
V. Biological processes:
Oxidation of organic matter by its use as food for organ-
isms which thereby effect its destruction.
Death of objectionable organisms, resulting from the
production of unfavorable conditions, such as absence
of food (removed by the purification processes) kill-
ing by antagonistic organisms, etc.
VI. Aeration:
Evaporation of gases held in solution and which are the
cause of objectionable tastes and odors.
Evaporation of carbonic acid, a food supply for some
kinds of growths.
Supplying oxygen necessary for certain chemical purifi-
cations, and especially necessary to support growths
of water-purifying organisms.
Vn. Boiling:
The best household method of protection from disease-
carrying waters.
These are the most important ways in which water is
cleaned and purified, but the classification is necessarily
imperfect and inadequate because each of the actions
mentioned is related to and grades into some of the
others, and in many cases it cannot be determined how
much of the purification effected by a given process is
brought about in one way and how much in another.
For instance, in filtration it is known that the straining
out of suspended matters, the sedimentation taking place
in the pores of the filtering material, and that adhesion
of the suspended particles to fixed particles of filter-
84 METHODS OF PURIFYING WATER.
ing material, are all important in bnnging about purifi-
cation, and in addition, there is also taking place at the
same time and in the same place a whole series of biologi-
cal changes, so complicated that at the present time only
a general outline of their nature is understood.
In a similar way, coagulation is usually effected by a
chemical process, and some chemical change in the
water is produced by the treatment, although this is not
its direct and principal object.
Sometimes two processes are combined, as where river
water is softened by chemical treatment in such a way
as to produce a coagulating effect upon the suspended
matters.
Many of the poisoning operations are by the use of
very powerful oxidizing agents. Ozone and chloride of
oxygen are among the most powerful oxidizing agents
known. In addition to killing the objectionable organ-
isms, there is sure to be direct chemical action resulting
from these substances which tends to the purification of
the water, and at the same time to the destruction and
elimination of the applied substances from the water.
These secondary actions are often of great importance.
If ozone is applied to a dirty water in quantity sufficient
to kill the objectionable organisms in clean water, it may
happen that the impurities in the water will absorb and
use up the ozone so rapidly that it will not have a chance
to act upon the organisms, and the desired effect will not
be produced. For this and other reasons it is not advis-
able to apply such oxidizing agents to dirty raw water.
So far as they can be used with advantage they must
be applied to waters that have already been filtered and
STRAINING. 85
oxidized and largely purified by other and cheaper
methods.
Straining. This is used particularly to remove fish
and floating leaves, sticks, etc. Coarse screening is best
effected by passing between steel bars arranged to be
easily raked off. Fine screening is most frequently done
through screens covered with wire cloth, arranged in
pairs so that one screen is raised for cleaning while its
mate is below in service. Such screens are often made
large and heavy and are raised by hydraulic or electric
power.
Revohnng screens are also used, and they are better.
They are of two general types. In one the screen runs
as a link-belt over pulleys above and below; in the other
the screen is in the form of a cylinder partly immersed in
the water and passing between guides which insure the
passage of all the water through it. In either case the
motion of the screens is continuous, and cleaning is done
in the part of the screen above the water by jets of water
playing upon it.
Screens are largely used in paper mills, wire cloth
having as many as sixty meshes per lineal inch being
often employed.
Many elaborate screening arrangements have been
installed for imfiltered reservoir waters, in the hope that
algae and other organisms would be removed by them.
Some organisms are removed, but the most troublesome
ones and their effects are not removed or even sensibly
reduced by screening.
Screening as a preliminary to filtration is often used,
and within certain limits is advantageous; but close
86 METHODS OF PURIFYING WATER.
screening is unnecessary, and in many plants there is no
screening before filtration and no need of it.
Sedimentation. This consists iti taking water through
tanks or basins in which the velocity of flow is reduced
and the heavier suspended matters are taken to the bot-
tom by gravity. The accumulated sediment is removed
from time to time. Sedimentation is widely used as a
preliminary process and is the cheapest way of removing
those relatively large particles which will settle out in a
moderately short length of time.
It pays to remove such particles in this way when they
are numerous, even though other and more thorough
processes are to follow, as the subsequent processes are
more easily and effectively carried out in the absence of
heavy suspended matters.
Scrubbers. These are rapid, coarse-grained filters, or
their equivalent. They have been used to a consider-
able extent in recent works. To some extent they are
used in place of sedimentation, doing about the same
work, but doing it quicker and in less space, though usu-
ally at greater cost; and to sQme extent they carry the
process further, removing smaller and lighter particles
than could be readily removed by settling alone.
Scrubbers act in part as strainers, but the principal
action is apparently the sedimentation which takes place
in the pores of the scrubbing material, where conditions
of sedimentation are extremely favorable.
It is very easy to build a scrubber to do good work. It
is more difficult to build one to do this and also be
capable of being cleaned in a cheap and efiicient man-
ner. From the standpoint of design and construction,
Interior of Filt«r House. Little Falls Filters of the East Jersey
Water Company, showing operating table for mechanical
filter.
Courteay of Mr. G. W. FuUar.
J*
•
MECHANICAL FILTERS. 8/
the cleaning devices are the most important parts of a
scrubber.
Mechanical Filters. This is a most important type of
apparatus. It is an arrangement for passing water
through a sand layer at a relatively high rate, with devices
for cleaning the sand when it becomes dirty, by revers-
ing the current, and by other means, and of all necessary
auxiliary apparatus for regulating and controlling the
process.
The term mechanical filter came from the mechanical
nature of the appliances used for cleaning the sand.
There are many types of mechanical filters and there
has been a great development in the devices used. The
substitution of concrete, bronze, and other durable
materials for the wood and the rapidly corroded iron
and brass of the earlier designs, is conspicuous, but in
addition, developments in the direction of simpler and
more adequate and effective devices have been most
important.
From the standpoint of design and construction the
cleaning de\ices offer far greater difficulties than the
filtering devices.
In mechanical filters the straining action is probably
more important than the sedimentation taking place in
the pores of the filtering material.
In a few cases mechanical filters have been used as a
first or preliminary process, but usually they are em-
ployed as a final process of purification. To make them
effective in this way the water reaching them must be
thoroughly prepared by coagulation or otherwise. That
is to say, all extremely small particles must have been
88 METHODS OF PURIFYING WATER.
drawn together into aggregates of sufficient size to be
capable of being removed by filtration at a high rate, and
the total amount of such particles must have been re-
duced by subsequent sedimentation to such a quantity
that the filtering material will not be too rapidly clogged
by them. Without such thorough preliminary treat-
ment mechanical filters are not capable of removing the
bacteria, or the finely divided sediment or turbidity, and
many other matters requiring to be removed.
Sand Filters. Sand filters are used at a lower rate than
mechanical filters, and cleaning is done by removing by
scraping of a surface layer of dirty sand instead of by
washing the whole sand layer by a reverse current. The
cost of cleaning devices being saved, and construction
simplified in other ways, as compared with mechanical
filters, a far greater filtering area can be provided for the
same cost; and filtration being at a lower rate, the strain-
ing action is more thorough, and there are opportunities
for biological purification. Sand filtration alone, without
preliminary treatment, is able to remove nearly all of the
objectionable bacteria, as well as other organisms, from
many waters, at the same time purifying them in other
ways. The straining is not close enough, however,
to remove the clay particles that render many waters,
especially some river waters, turbid, and such waters
require preliminary treatment.
Sand filters are used in connection with various pre-
liminary treatments, but, generally speaking, they are
adapted to treating only such waters as are capable of
being purified in that way without any preliminary treat-
ments, or with only rough and inexpensive treatments
basic to another at Omaha, .'
Aeration of wat«r in falling over a atone dtun.
► • •
*
«
COAGULATING BASINS. 89
If the water ordinarily requires coagulation, then, as a
rule, it will be better to make the coagulation thorough
and use mechanical filters for the final treatment.
Coagulating Devices. Coagulating devices consist of
apparatus for dissolving the chemical or chemicals used
for coagulating the water, and for mixing the solutions,
and bringing them to the required strengths, and for ap-
plying them to the water, and mixing them with it, and
all auxiliary appliances.
There is great variety in coagulating devices, and much
ingenuity has been displayed in meeting special condi-
tions. There is no great or insuperable difficulty in se-
curing the regular and proper addition of coagulant to a
water, and in many cases this has been done in a perfectly
satisfactory way. On the other hand, the coagulating
devices have probably failed to act more frequently than
any other part of the plants of which they form parts,
and for this reason the greatest care must be given to
their design and operation.
Coagulating Basins. Coagulating basins arc required to
hold the water for a time after it has received the coagulant
or coagulants, to allow the chemical reactions resulting
from the treatment to take place. They also serve to re-
move by sedimentation the greater part of the precipitate
that results from these reactions. This feature is of the ut-
most importance, as otherwise the precipitate would choke
the filters, and cleaning would be required too frequently.
The bulk of the precipitates should always be removed
before the water goes to the filter, and to this end baffles
and other devices tending to complete sedimentation are
desirable, and the bottoms of the basins are made with
go METHODS OF PURIFYING WATER.
slopes and gutters to facilitate the easy and frequent
removal of the mud which is deposited upon them.
Aerating Devices. Aerating devices are used to bring
the water in contact with air, either for the purpose of
introducing oxygen or of removing carbonic acid or
gases which produce tastes and odors. The natural
flow of water in the bed of a mountain stream having a
rapid fall aerates it in a most effective way, and many
works are so arranged that this kind of aeration is uti-
lized. Flow in sluggish streams or canals has compara-
tively little value for aeration.
When aeration must be done with artificial appliances,
playing the water in jets forming fountains is one of the
most effective ways, but to be thoroughly efficient con-
siderable head is used up, and this is a serious obstacle,
when the water is pumped, because of the cost. In other
cases the water is allowed to fall through the perforated
bottoms of trays, and similar devices. Under some
conditions flowing over or through coke or other coarse-
grained ballast seems to aid, but it is essential that the
air in the voids of such material should be frequently
changed by some certain means, as otherwise the materials
instead of being helpful will greatly reduce the amount
of aeration obtained.
When aeration is used to introduce oxygen, a sub-
stantial result may be obtained by well designed appli-
ances with a drop of not more than two or three feet in
water level. Much more extended aeration is required
to remove objectionable gases from a water, and a
greater head may be advantageously used where they
are troublesome.
m
Coagulating Devices at Watertown, N. Y.
fe^..
*
:.«S^
1
^.,
AERATING DEVICES. 9I
Intermittent filters can be operated so as to thoroughly
aerate the water passing them, so Icng as the water quan-
tity and the amount of organic matter in it are not too
large, having reference to the grain-size, depth, and
condition of the filter sand; and for this reason this form
of filtration has advantages when much aeration is
required.
The above outlines of the most important processes
of water purification, and of the appliances used to carry
them out, is intended only to give a general idea of what
is aimed at, and of the objects of the various parts of the
works, and no detailed descriptions are necessary for
this purpose. In the same way only those methods and
appliances of some practical importance are included.
A great number of other processes have been proposed,
and a few of them may be in time developed so as to be
of practical value. But a discussion of such processes,
not yet brought to successful application, would not aid
in a clear understanding of first principles.
It is worth noting that most of the advance in water
purification comes from the development of old processes.
It is only at long intervals that a new method or principle
of treatment is discovered that is important enough to
find a permanent place in the art.
V
CHAPTER IX.
ON THE APPLICATION OF THE METHODS OF WATER
PURIFICATION, ARRANGED* ACCORDING TO THE
MATTERS TO BE REMOVED BY THE TREATMENT.
Tastes and Odors. Tastes and odors are to be most
frequently found in waters from impounding reservoirs
and small lakes, and in our climate such waters are sure
to have tastes and odors at times. They have occurred
even in those reservoirs where the greatest efforts have
been made to prevent them by cutting out shallow flow-
age and by stripping the reservoir bottoms of soil.
Aeration to Remove Tastes and Odors. The simplest,
cheapest, and most generally applicable method of remov-
ing tastes and odors is by aeration; that is to say, by
bringing the water in contact with air by playing the
water into it by fountains or otherwise. The natural
flow of water in the bed of a mountain stream over stones
and ledges aerates it very well. The exposure of water
to the air in reservoirs and in gently flowing rivers or
channels certainly tends to aerate it, but far less effect in
removing tastes and odors is usually observed from such
exposure.
To throw water up in a fountain, which means a con-
tact with the air not exceeding usually two or three,
or at the most, four seconds, would seem a very slight
treatment for water which has been exposed to the wind
92
MECHANICAL FILTRATION. 93
action in a reservoir for weeks or months, but it will
often do what the long exposure has not accomplished.
Among the cases where a striking improvement in
tastes and odors has followed aeration may be mentioned
the following:
Ludlow Reservoir water, played through fountains to
Van Horn Reservoir at Springfield, Mass., in the summer
of 1905. (This was the first year the fountains were used;
the supply was filtered in 1906.)
Grassy Sprain Reservoir water, pumped over an
aerating device into the Fort Hill Reservoir at Yonkers.
Water from several impounding reservoirs, let down
through natural channels to the old Croton Reservoir
supplying New York City.
Water let down in the same way from the main upper
reservoirs to the small intake reservoir at Newark.
Such aeration always reduces, and sometimes removes,
tastes and odors from the waters of the reservoirs and
small lakes, whether resulting from putrefaction in sum-
mer in the stagnant bottom water or from growths of
organisms in the surface water.
Mechanical Filtration to Remove Tastes and Odors.
Mechanical filtration was used at Wilkesbarrc, Pa., for
treating a reservoir water. It did not sufficiently remove
tastes and odors, and for this reason the plant was aban-
doned.
At Charleston, S. C, Goose Creek water, which is sub-
ject to very bad tastes and odors, is successfully purified
by a process of which mechanical filtration is one
step.
The whole process consists of the following:
94 THE APPLICATION OF METHODS.
(i) Use of copper sulphate in the reservoir to hold
down growths of organisms.
(2) Aeration of the water.
(3) Coagulation, followed by passage through a basin
holding two days' supply.
(4) Aeration of the water on leaving the basin.
(5) Mechanical filtration.
(6) Aeration on leaving the filters.
In the above process the three aerations were not used
at first, and without them the tastes and odors were not
removed. The addition of the aeration at the places as
stated served to make the process reasonably efficient.
In general it may be stated that mechanical filtration
is not efficient in removing tastes and odors. Probably
in most cases when improvements have followed it, they
have resulted more from the incidental aerations than
from the filtration.
Sand Filtration to Remove Tastes and Odors. Sand
filtration has considerable power of reducing, and in
some cases of removing, tastes and odors, but it is not
usually to be wholly relied upon when the raw water is
very bad.
In England it is used for treating water from impound-
ing reservoirs, and seems to be usually efficient in remov-
ing such tastes and odors as there are; but these tastes
and odors clearly are far less serious than those in many
or most American reservoir waters.
At Reading, Pa., with impounding reservoir waters,
subject to moderate but not extreme tastes and odors,
filtration at a rate of from 3,000,000 to 5,000,000 gallons
per acre daily is sufficient.
Aeratton of Hemliirk Liike water at Riicliester, N. Y., resulting
in a rwiiiction of tastes iinil c«lor<.
Courtesy of Mt. EmU Kuichling.
• •
• • "
INTERMITTENT FILTRATION. 95
At Springfield, Mass., experiments indicated that such
filtration, even when accompanied by aeration, would
not suflice to deodorize the water from Ludlow Reservoir,
which is exceptionally bad. In this case putting the water
through two filters in succession, with aeration before,
between, and after, did serve to fully remove the odors.
Intermittent Filtration to Remove Tastes and Odors.
Intermittent filtration is a term appUed to filters of special
construction and operation. The filters are usually
drained at the bottom and the outlets are always open to
let any water that gets through the filter sand flow away
without obstruction. The water to be filtered is applied
rapidly to the surface at intervals, with periods of rest
between, during which the surface of the filtering ma-
terial is exposed to the air, and the sand becomes drained.
The sand is preferably rather coarser than would be used
in ordinary filtration.
Intermittent filtration has been particularly successful
in purifying sewage. It is also used for treating manu-
facturing wastes containing much organic matter. It is
successful for these purposes because it brings the organic
matter in the Uquid in contact with more air, and in more
intimate contact with air, and for a longer time, in the
pores of the sand than can be secured in any other way.
This contact is essential for the oxidation of the organic
matter.
The reason why ordinary or continuous sand filtration
failed to remove odors in the Springfield tests seemed
clearly to be that the water carried more organic matter
than could be disposed of by all the oxygen present,
including that furnished by the aeration.
96 THE APPLICATION OF METHODS.
It seemed reasonable to suppose that if more air could
be brought in contact with this water the process might
be made successful, and the method of intermittent fil-
tration successfully used for this purpose in sewage puri-
fication appeared to be the best way of accomplishing
this end.
The condition of the water at Springfield being
extremely unsatisfactory, this process seemed worthy of a
trial. The local conditions proved exceptionally favor-
able for the construction of this kind of filters. A bank
of sand close to the reservoir was found which was of
such a quality that it could be used just as it came from
the bank for filter sand.
This was leveled off to form a filtering area of about
four acres. This was underdrained. No water-tight
bottom was provided. Expense was thus saved, though
some water is lost, and this seeps back to the reservoir.
A pumping station lifts the water to an aerator, from
which it flows through gates to the four divisions of the
filters. The pump is operated about i6 hours daily,
the filters being left to drain for the other eight. The
plant was built for temporary use only, as a new supply
is authorised. It cost $50,000 to build, and has yielded
about 12,000,000 gallons a day of water substantially free
from tastes and odors, and otherwise improved in quality.
The cost of operation, that is to say, of pumping the
water, of caring for the filters and renewing the surface
sand, and of maintaining a small laboratory, which is
necessary for the operation, with supervision, is five or
six dollars per million gallons.
This plant is not capable of operation in winter, and it
O w *
COLOR. 97
is not expected to have a high bacterial efficiency, and
it would not therefore do for use where the water was
subject to pollution.
Intermittent filtration probably has no advantage over
ordinary sand filtration with thorough aeration in remov-
ing tastes and odors, in those cases where the amount of
organic matters associated with them arc not excessive;
that is to say, where they do not exceed the amounts
which the air present in such filtration is able to dis-
pose of.
But where the water is very bad indeed, intermittent
filtration with aeration is perhaps the most powerful
method at our disposal for removing tastes and odors.
The only alternative is the use of successive filtrations
with aeration between.
Color. The word color refers to soluble yellow color-
ing matter extracted from dead leaves, peat, and other
vegetable matters, and it is principally found in swamp
waters. As previously stated, it is found in many im-
pounding reservoir waters and in river waters in certain
parts of the country.
Color is not ordinarily removed to any considerable
extent by simple filtration through either sand or me-
chanical filters.
Color is slowly bleached and destroyed by sunshine.
In large impounding reservoirs this is often a matter of
importance, but the action is too slow to be considered
in artificial purification.
Ozone destroys color. If it were not for the large cost
of producing the ozone, this would be the most desirable
method of removing it.
98 THE APPLICATION OF METHODS.
Color is rendered insoluble by certain coagulants and
therefore capable of removal by filtration. Sulphate
of alumina is most commonly and successfully used for
this purpose, and this is at present the usual and most
feasible way of removing it.
There are a great many filter plants treating water that
is more or less colored, with sulphate of alumina, and
successfully removing most of the color. Among these
the following may be mentioned.
Norfolk, Va., where a very highly colored water from
small lakes and streams is used. This water is coagu-
lated, stored in a natural basin *to allow the action to
become completed, and is then passed through mechani-
cal filters of the so-called Jewell type.
Charleston, S. C, where the water is treated as pre-
viously described in connection with tastes and odors.
The sulphate of alumina used in the treatment serves to
decolorize the water. As there is not enough alkalinity
naturally present in Goose Creek water to react with the
coagulant and to combine with the acid constituent of it,
lime is added to the water in sufficient amount to do this.
The lime so added does not act as does lime added to a
naturally hard water. There is no precipitation of lime.
The whole amount added remains in solution and makes
the water so much harder.
Watcrtown, N. Y., where Black River water is coag-
ulated with sulphate of alumina, and is then filtered
through mechanical filters. Soda ash is used to make
up deficiency in alkalinity on the few days in the year
that it is necessary.
All the above mentioned waters are very highly colored
FERMENTATION OF COLORING MATTER. 99
and are satisfactorily decolorized by the treatment. If
smaller plants and less deeply colored waters were in-
cluded, the list could be indefinitely extended.
The use of iron sulphate with lime in place of sul-
phate of alumina has been tried, especially at Quincy
and Moline, 111.; but for color removal this treatment
appears to be clearly less satisfactory than the usual sul-
phate of alumina treatment.
Fermentation of Coloring Matter in the Stagnant Bot-
tom Water of Impounding Reservoirs. When highly
colored water is stored in an impounding reservoir, and
the bottom water goes 'through the putrefaction process,
it does not directly reduce the color of the water, but it
does change the chemical nature of the coloring material
in such a way that it may afterwards be removed to a
considerable extent by filtration without chemical treat-
ment.
The river waters filtered without coagulation at Law-
rence, Albany, and many other places, are more or less
colored. And some of this color is always removed by
the filtration. The amount of removal ranges from a
fifth to a third. As a general average a reduction of
25 per cent is obtained. And in the filtration of reser-
voir waters that have not been through the putrefactive
process about the same proportion of removal is obtained.
On the other hand, highly colored waters from deep
reservoirs are often easily and almost completely decol-
orized. In visiting the Rivington works of the city of
Liverpool in 1896, the writer was deeply impressed with
the almost complete removal of the high color of the res-
ervoir water by simple filtration through ordinary sand
lOO THE APPLICATION OF METHODS.
filters. In the experiments at Springfield on the Ludlow
Reservoir water to remove tastes and odors a very high
degree of color removal was obtained, and the filters
since built to deodorize the water also serve to decolorize
it to an extent that would be altogether impossible with
river water or with reservoir water which had not been
subject to putrefaction.
At Charleston, S.C., with Goose Creek water, coag-
ulant is used, but the amount required to decolorize the
water is much less than would be necessary for the treat-
ment of a river water of equal color. In this case it is
to be noted that Goose Creek Reservoir is far too shallow
to have a permanent stagnant layer; but nevertheless
very strong putrefaction changes do take place in the
water near the bottom. This water which has putre-
fied is mixed by the wind with top water from time to
time, and the whole body of water has to a large extent
the character of bottom water from a deep reservoir,
and at the same time it contains the organisms usual in
top water.
The putrefaction may bring about some changes in
the coloring matter itself, which renders it more easy of
removal, but the principal cause of the change in char-
acter seems to be associated with the condition of the
iron that is always present in these waters. During the
putrefaction the oxygen dissolved in the water is exhaus-
ted, and the iron is reduced from the ferric to the ferrous
state. Iron is freely taken into solution under these
conditions from the materials of the bottom of the reser-
voir, and these are pretty sure to contain a sufficient
supply of it. The bottom stagnant water of reservoirs
>. <
^ ' : :
n k
ACnON OF IRON ON COLOR. lOI
nearly always contains far more iron than the water
entering the reservoir.
Now when this water is aerated the iron is oxidized
again to the insoluble ferric state. If there is enough
iron present in proportion to the coloring matter, it will
precipitate out forthwith. In doing this it acts as a
coagulant upon the coloring matter and removes it. If
the amount of iron is small in proportion to the coloring
matter, then the organic matter will hold the iron in
solution even in the ferric state; but the combination is
not quite stable and is easily broken up. It is more
likely to be broken up and removed in a filter than in a
reservoir. There are three possible conditions resulting
from the putrefaction followed by aeration, depending
upon the relative amount of iron and coloring matter,
and how far the putrefaction has gone, namely (i ) there
may be an immediate flocculent precipitate, such as
would be thrown down by sulphate of alumina; or (2)
the water may show no physical change, but still be in
condition where the matters will be removed by filtration
without further preliminary treatment; or (3) the com-
bination of iron and organic matter may be too stable
for removal by filtration; but it has nevertheless been so
far changed that it can be removed by a smaller amount
of coagulant than would otherwise be necessary for the
removal of the coloring matter.
The action of iron in reservoirs, its accumulation and
separation after aeration, were studied by the late Dr.
T. M. Drown, and by Mr. Desmond FitzGerald and
others in Boston, especially about 1890-93, and became
fully understood at that time; but more than ten years
I02 THE APPLICATION OF METHODS.
elapsed before practical advantage of these actions was
taken in decolorizing water. In England, it is true, it
plays, and for many years has played, an important part
in cleaning reservoir waters; but this seems to have been
rather accidental than intentional, and there seems to be
no reason to believe that the process was ever thoroughly
understood or that efforts were made to facilitate it.
It is probable that in future much more extended use
will be made of this method of decolorization of reservoir
waters, especially as the treatment is also substantially
that adapted in the removal of odors and tastes from
these waters, and the two objects are thus secured by the
same treatment.
Turbidity. Practically the turbidity question may be
limited to river waters. Lake and reservoir waters are
occasionally turbid, but seldom in a way to be seriously
troublesome, or to such an extent that they cannot be
removed by methods of treatment which might be
adapted to purify the waters in other respects. All
river waters are more or less turbid at times, but the
differences between different river waters are vety great
indeed.
In a general way the turbidity question is not a diffi-
cult one in that part of the United States which was once
covered with glaciers. South of this area turbidity is of
such importance as practically to control the methods of
treatment that must be used. This division obviously
is a rough one, with many exceptions both ways, but it
does represent the predominating conditions.
The conditions in the northern or glaciated area corre-
spond more nearly with European conditions, and it is
Coagulating and sedimentation ba
water and witli lliorougli baffling
South Pittsburgh filters.
Coaigulating and sedimentation basin with baffles and pumping
station anrf filter house at St. Josepli, "'
Courteay of AmerlcsD Water Works and Giu ran
TURBIDITY. 103
in this area only that comparisons with European prac-
tice are helpful.
In water purification there are two matters to be ascer-
tained as to turbidity. First, how much turbidity is pres-
ent in the water; and second, how small are the particles
that constitute it.
If the turbidity is sufficiently coarse grained, it can be
removed by sand filtration without previous chemical
treatment. If it is present in large amounts, it can be
cheaply removed in part in settling basins, and in this
way the work of the filters can be lightened, and the cost
reduced. And that work can be still further lightened
by the use of preliminary or roughing filters, which do
the work of sedimentation basins, but perhaps more
quickly and more thoroughly.
Much of the turbidity of certain northern rivers is of
this coarse-grained variety, but it is seldom present in
large amounts, or continuously; and when it is only pres-
ent once in awhile, investment in roughing filters or even
in sedimentation basins may be of doubtful economic
value. It is very easy to spend on such works more than
can possibly be saved in the cost of the subsequent
filter operation.
Altogether the coarse-grained turbidity does not pre-
sent a very serious problem in water purification.
In that part of the country which was not glaciated,
and this includes the lower Susquehanna basin, much
of the Ohio basin, and the Missouri basin, and all to
the south of them, turbidity is often present in large
amounts, and it is usually composed of extremely fine
grains, and the water often runs turbid in the streams
TURBIDITY. ir-2
in this area only that comparisons with Eur;i:r_^:L ziraz-
tice are helpful.
In water purification there are two mzv.-^n :: ix -.izs-
tained as to turbidity. First, how much -.urbli— i.- "^
ent in the water; and second, how small trt u;-. i^--:u^
that constitute it.
If the turbidity is sufficiently coarst- 2T-:i;^-- -■ —l Jt
removed by sand filtration without pri:v'-.._r .'^-rz-jH
treatment. If it is present in large h,cj:.u::-.- / -- -i
cheaply removed in part in setthng btiii.:-.. --i i -—•
way the work of the filters can be lighi^^'i. iz.: ■.■^- .:■•:
reduced. And that work can be still :u.-.l- lz::-"-
by the use of preliminary or rouehliiz ijr.-r^r. ■■ •— : 'y.
the work of sedimentation basins. V-: y^ri^y " -'-
quickly and more thoroughly.
Much of the turbidity of certain z.:<rj:rr-- .-. tr. ■ -A
this coarse-grained variety, but i: '.- s^i.-.c ',rt-^:-. ..-.
large amounts, or continuously; and t'xl .: .■ :r.._ ;.-■;-.-
ent once in awhile, investment in ''s:.z"T '-.-". ■,- -: '-.r.
in sedimentation basins may be '.: z:-..'!.. f.-.^.-.TT.'.'.
value. It is very easy to spend o:: ;Xi t .'tc-. -.:•=: ::.>.7.
can possibly be saved in the c-jt: -.:' :::.^ ■,'.■■/:.,':-'.
filter operation.
Altogetlier the coarse-grained rr^ii':/ -i-yr- r.-r :,r-:-
sent a very serious problem in »-E:*T_",T;:V.i::',r.,
In that part of the countn- tc>.:- i-i., - ,-. :^>.- : -■. '. .
and this includes the loner SusC3*i^-..-.s ■A.-.'.r.. ::. .
of the Ohio basin, and the Misyy:.-: rA,:.'j, >.--■; ^^ --
the south of them, turUdity is '>J-,*r. ^r'r-f.r.*, :.-. ^---^
amounts, and it is usually canpwK of •■-/Xt':::. ■ -^,
later <rfta rau taru'i ''. •■- - .'-^—
104 THE APPLICATION OF METHOD&
continuously for weeks and even for months at a time.
In fact there are some rivers of which the waters are
nearly always turbid.
There is one known way of removing turbidity from
these waters, and only one; that is by coagulation
or chemical precipitation.
Without such treatment, no amount of filtration, single
or double, or multiple, will remove it. With such chem-
ical treatment adequately carried out, the simplest and
easiest filtration will suflBce to make the most refractory
water as clean as distilled water.
There are a number of chemical treatments that are
used, according to habit and other circumstances. These
are all closely related to each other, and are frequently
combined to a greater or less extent so that strict classi-
fication is not possible.
The substance first and most generally used for this
treatment is sulphate of alumina.
When the amount of lime naturally present in the
water is not sufficient to effect a complete reaction with
it, lime must be added in connection with its use. Soda
ash may be used in place of lime, at somewhat greater
expense, but with the advantage that the water is not
hardened. Generally, however, there is enough lime
present for the reaction in excessively turbid waters, and
the use of lime for this purpose is not very common.
Sulphate of iron, or copperas, is also extensively and
successfully used in treating turbid waters. A greater
degree of alkalinity is required to precipitate this sub-
stance, and lime must always be used in connection with
it And by using more lime, some of the lime naturally
TURBIDITY, 105
present in the water can be thrown down together with
that added, thereby softening the water as well as remov-
ing the turbidity from it.
Under some conditions it would seem that the pre-
cipitation of the lime and magnesia of the water by lime
alone would at once soften it and suffice to coagulate the
turbidity, but it does not seem likely that this reaction
can often be fully depended upon. The lime and mag-
nesia precipitates do not have as great a coagulating
value as those of iron and alumina.
Lime and iron are cheaper than sulphate of alumina,
and there are great advantages in their use in large plants.
Their application is much more difficult to control ade-
quately, and it should not be undertaken except with the
assistance of a competent resident chemist and good
appliances for adding the lime in any quantity that may
be required by the composition of the water.
This method of treatment leaves the water with an
imnatiiral deficiency of carbonic acid. It is necessary
that the carbonic acid should be absent to allow the reac-
tions to take place which result in the coagulation. But
there is a question as to the desirability of supplying
water for use in this condition. Such water always tends
to deposit a coating of lime upon everything with which
it comes in contact. This is more apt to be the case
where the coagulating basins in which the reactions take
place are not very large.
It has usually been thought necessary to restore to the
water a normal amount of carbonic acid at the end of
the process. This is done, for example, at the softening
plant at Winnipeg, by burning coke and allowing the
I06 THE APPLICATION OF METHODS.
water to fall a short distance through a space containing
the products of combustion of the coke, of which products
of course carbonic acid gas is the important one.
At St. Louis the water is subjected to the iron and
lime treatment, followed by subsidence in large basins,
in which the bulk of the precipitate settles. The par-
tially purified water is then sent to the city without filtra-
tion or recarbonating, or other treatment. While the
result is very far from ideal, the improvement over pre-
vious conditions is so marked as to be generally satisfac-
tory.
Softening. Softening in connection with the treatment
of turbid river waters has just been mentioned. Ground
waters are also softened. In fact, up to the present time
most of the softening that has been done has been of
ground water.
The method is that of the old Clark process. The
lime of the water is precipitated by other lime that is
added to the water for that purpose, and the resulting
precipitate of carbonate of lime is settled, strained, or
filtered from the water. There are many appliances for
carrying out this^ process. Most of them are specially
adapted to moderately small plants, such as those soften-
ing water for boiler-feed purposes. Such plants have been
extensively installed by the railroads in some parts of
the country, and also by manufacturing establishments.
Winnipeg, Canada, has the most important municipal
plant in America for softening ground water. Oberlin,
Ohio, softens reservoir water. In addition there are the
plants which in connection with other treatments partially
soften river waters.
IRON REMOVAL. 10/
Iron Removal. Iron is troublesome only in ground
wafers. Its removal is a distinct process, rarely com-
bined with purification for any other purpose. In most
cases the iron can be removed with such ease and with
such simple appliances that the purification is easier and
cheaper than any other water treatment except the re-
moval of odors by aeration.
It is simply necessary to thoroughly aerate the water
to remove the excess of carbonic acid, and introduce the
oxygen needed to oxidize the iron from the soluble ferrous
state in which it exists in the water, to the insoluble ferric
state. It can then be removed by filtration. The pre-
cipitated iron is very easily removed, and the filtration
may be rather rapid, and the appliances simple and
inexpensive.
Occasionally, as at Reading, Mass., and at Superior,
Wis., the iron is held more firmly in solution in some
unknown way and will not separate so easily. In these
cases either one must be contented with a partial removal
(which may, however, answer practically very well) or
more vigorous chemical treatment must be given.
Removal of the Effects of Sewage Pollution The
problem of removing the effects of sewage pollution from
a water by artificial purification is, from a sanitary stand-
point, the most important of all, and the one that occurs
most widely. It is also the one which has been longest
and most carefully studied and in regard to which there
is the most information.
Sewage pollution is most important in river supplies,
as practically all large river waters are more or less
subject to it. It is also important in many or most sup-
108 THE APPLICATION OF METHODS.
plies from large lakes. It is far less important for sup-
plies from small lakes and impounding reservoirs, but
even in such cases there is often population upon the
catchment areas which makes it worth while in selecting
a method of purification to get one that is capable of
dealing with the effects of sewage pollution.
This can be done without difficulty. The methods of
purification adapted to the removal of turbidity and color
are also adapted to bacterial or hygienic efficiency, al-
though many precautions must be taken which would
be unnecessary if there were no hygienic conditions to
be met.
Sand Filtration, for the Removal of the Effects of Sewage
Pollution. On the whole, the best results in water puri-
fication, as measured by the improvement in the health
and the reduction of the death rate among those who use
the water, have been obtained with sand filters. This
is probably because the method is an old one, has been
long and carefully studied, and has been applied on a
large scale in well perfected forms for many years, rather
than to any natural superiority of the method. There
are also cases where inadequate purification has been
obtained by this method, resulting from defective con-
struction or from defective operation, where sickness and
death have resulted. But such cases have not occurred
in plants of the better class which are carefully operated.
Mechanical Filtration, for the Removal of the Effects
of Sewage Pollution. Most of the mechanical filters
now in use in America have fallen very far short in
hygienic efficiency. The greater part of them are of
old and inferior types.
HYGIENIC EFFICIENCY. IO9
Even with these old plants with skilful manipulation
it is often possible to get fairly good results; but these
older plants have seldom had skilful, and often not
even intelligent, manipulation; and it is no wonder that
they have so often fallen short of what was expected of
them. It is rather to be wondered that with the appli-
ances and men that have been used, so much has been
accomplished with them.
All the larger and more recent plants of this type have
been equipped with many devices for performing the
various operations better than was formerly possible, and
also for doing them more certainly; and in these newer
and better plants it has been customary to install a labo-
ratory and to employ a superintendent of experience in
operating filters and training in hygiene and bacteri-
ology, to ascertain what is being done at all times.
This super\dsion has led to great improvements in
methods, which were only possible through close and
continued study under the actual conditions of operation;
and it has done more than all else to insure regularly
good results.
At present the mechanical filters of the country that
have been constructed and operated in this way are doing
as good work, measured by bacterial efficiency, as the
corresponding sand filter plants; and there is reason to
believe that in time the death rate data will show corre-
sponding results from them.
Other Methods of Purification for Hygienic Efficiency.
The hygienic efficiency of other methods of purification
need be mentioned only in a very brief way.
Intermittent filtration, as used at the Ludlow Reservoiri
no THE APPLICATION OF METHODS.
Springfield, Mass., has considerable power of bacterial
purification, but is by no means equal in this respect to
filters of standard construction. The same may be said
of the processes of iron removal by aeration and rapid
filtration, but in this case the bacterial efficiency will be
greater as the amount of iron is greater and exerts a
greater coagulating effect upon whatever suspended mat-
ter, including the bacteria, there may be in the water.
There is no reason to believe that the preliminary filtra-
tion or scrubbing of water, to be afterward passed through
sand filters, contributes to any substantial extent to the
efficiency of the process as a whole, precisely as there is
no reason for believing that it makes any great difference
with the passage of finely divided turbidity through the
final filters.
Ozone has been advocated as an auxiliary to filtration
for the purpose of killing any germs left in the cffl.icnt
from the filters. Ozone has the power of doing this when
used in sufficient quantities. But the quantity required
to be effective is considerable, and with present methods
the cost of producing it seems disproportionately large
for the results that can be obtained.
Hygienic Standards of Purification. In the last years
there has been a well marked tendency for water purifi-
cation methods to crystallize about certain standards.
These standards are those in the different methods which
serve to reduce the turbidity and color to inappreciable
amounts, and which in general remove something like
99 per cent of the bacteria when those organisms resulting
from sewage pollution are fairly numerous. And such
filtration, in a genei'al way, costs, including all operating
HYGIENIC STANDARDS OF PURIFICATION. Ill
expenses and 5 per cent on the required capital, something
like $10 per million gallons of water treated.
There is no final reason for such standards. They
have been adopted by consent because they represent a
purification that is reasonably satisfactory and that can
be reached at a cost which is not burdensome to those
who have to pay for it.
Such purification makes the waters of some of the most
highly polluted rivers used for public water supply in the
United States, as for example, the Merrimack and the .
Hudson, as safe hygienically and as satisfactory in every
way as supplies drawn from far better sources, as far as
the* results can be measured by the best means at our
disposal, namely, by bacterial tests and by the records of
the Health Departments of the various cities where the
waters are used.
It is true that the most searching bacterial methods
usually disclose in such purified waters some bacteria
characteristic of sewage. The number of such bacteria
in the eflfluent is very small, when compared with those
in the raw water. In fact the proportion of such germs
removed is probably materially larger than the propor-
tion of germs of all kinds.
There is no evidence that the germs so left in the water
are in any way injurious. Certainly if injurious influ-
ence is exercised it is too small to be determined or meas-
ured by any methods now at our disposal.
In treating water for the removal of tastes and odors,
and for the removal of iron, and where hygienic efficiency
is not important because the raw water is entirely free
from sewage, many things can be done to reduce the cost
112 THE APPLICATION OF METHODS.
of filtration, and in such cases it is proper that they should
be done; but any filtration sufficient to remove color or
finely divided turbidity will approximate so closely to the
usual standards required for hygienic eflSciency that but
little added expense will be required to secure from it full
standard bacterial eflSciency. There is, therefore, not
much inducement to cut down the works and methods
for colored and turbid waters, even though in some cases
with little or no pollution it may be admitted that hygienic
eflSciency is not important.
The reverse proposition, however, is most important
when future conditions are contemplated. If we take
one per cent as a fair allowance for the proportion of
bacteria that are to be allowed to pass the filters, then it
is certainly conceivable, and even probable, that as time
goes on, and as the sewage pollution of our rivers increases
to many times what it now is, and as more searching
methods of investigation of the effects of water upon
health are discovered and used, a point will be reached
where a much higher degree of bacterial eflSciency will
be required. Present conditions do not seem to demand
it, but we must expect that at some time in the future
conditions will arise which will make it necessary.
When additional purification is required it can be fur-
nished. There are many ways in which it can be secured.
It will be enough to mention the use of lower rates of
filtration, of finer grained filtering materials, and of more
complete chemical preparation. It is idle to attempt to
decide now how the problem can be best solved when it
arises.
Even to-day, with the limit of cost raised, so that, for
LIMITS OF PURIFICATION. II3
example, the cost of the whole process might be raised let
us say to $20 per million gallons, works could be designed
which would remove the bacteria far more completely
than any works now in service are able to do.
The reports of the Lawrence experiment station show
many cases of purification going far beyond the usual
standards. The methods used to produce them have
not been practically adopted, for there is as yet no call
for such added efficiencies, and no justification for putting
the additional expense of securing them upon those who
use the water.
Even now, financial conditions would often justify
larger expenditures for water purification than are now
made, if adequate results could not be otherwise obtained;
and the instances where this is the case are sure to in-
crease rapidly as the years go by.
It may, therefore, be reasonably anticipated that far
more eflScient methods of purification will come to be
used in course of time, and in discussing the advantages
and disadvantages of polluted waters after purification
for use by cities through a long term of years with steadily
increasing amounts of pollution, it w^U not do to con-
sider only the methods of purification now in use. Bet-
ter methods will be available for the more diflScult
service when they are needed.
CHAPTER X.
STORAGE OF FILTERED WATER
Filtered water is in general to be stored only in cov-
ered reservoirs where it is not exposed to strong light
Ground water, which is water that has been filtered by
nature in passing through the soil, is to be treated in the
same way.
There are many cases where such waters are stored in
open reservoirs; in these cases the waters always deteri-
orate in quality, but not always to the extent of making
them inacceptable.
Deterioration takes place principally in warm weather.
It results from the growth of microscopic organisms in
the water. The mineral food supply (corresponding to
fertilizer on a wheat crop) is always contained in the
water and in the air. The organisms decompose car-
bonic acid always present in both air and water, with the
aid of the light, and build up from the carbon obtained
from it the organic matters of which they are composed,
precisely as the wheat plant builds up its structure from
inert mineral matters. If time and other conditions per-
mit, the organisms will grow until the water becomes
offensive with them, and the products of their grov/th
and decay.
Filtered waters are stored in open reservoirs, i.e., in
old reservoirs previously used for raw water, at Lawrence,
114
1
n
Interior of covered pure-water reservoir at Watertown, N. Y.
'4 •
• «
RESERVOIRS FOR FILTERED WATfeR. I r 5
Albany, Washington, Watertown, Paterson, Hackensack,
and many smaller places. In some cases not much trou-
ble has been experienced; in others, the conditions have
been far from satisfactory.
Practically all reservoirs built for filtered water in the
last years have been covered, and some old open reser-
voirs have been covered. This has happened more fre-
quently in the case of ground water supplies than in the
case of filtered water supplies.
The advantage of storing filtered waters in the dark,
where they will keep entirely without deterioration, is so
great that it seems certain that the present practice of
covering will be continued until the present open reser-
voirs are all abandoned or covered.
Covered reservoirs for filtered water have been built
at many places. Among them, at Albany, Watertown,
Ithaca, Yonkers, N. Y., Washington, D. C, Philadel-
phia, Pa., and by the East Jersey, Hackensack, Queens
County and Superior Water Companies. It should be
noted that in many cases there are several reservoirs,
some open and some covered in the same city.
CHAPTER XI.
ON THE REQUIRED SIZES OF FILTERS AND
OTHER PARTS OF WATER WORKS.
One of the most perplexing questions to a beginner is
to find the reasons for the apparent discrepancies in the
sizes of the different parts of a well designed water works
system. If a system is capable of supplying 15,000,000
gallons per day, it would seem at first thought that all
parts should be of this capacity and that nothing beyond
it would be necessary. But this condition is never real-
ized. The pumps have one capacity, the pipes another,
the filters still another, and the plant is declared to be too
small while the average consumption of water is below
any of the figures given for the capacities of the com-
ponent parts.
In laying out a system of works there is no matter
which calls for more careful study than the most advan-
tageous sizes of these component parts. To some extent
these sizes are not capable of calculation, but are matters
of judgment. The judgment to be valuable must be
based on extended experience, and must take into ac-
count all the particular conditions in the case in hand.
Let us take a particular case to illustrate in a general
way the method of getting at these sizes.
The city under consideration has a present population
of SOyOoo, we will say. The works now built should be
1x6
AMOUNTS OF WATER PER CAPITA. II7
large enough so that no addition will be required for ten
years. In some parts it may be worth while to anticipate
growths for a longer period. The rate of growth to be
anticipated is judged from the past rate of this particular
city, and of other cities similarly situated, taking also into
account any special conditions likely to make it grow
either more or less rapidly than it has done, or than its
neighbors. In this case we will say that, all things con-
sidered, 25 per cent per decade seems a reasonable al-
lowance. Adding 25 per cent to the present population
brings us to a population of 100,000, which must be
provided for in the first construction.
The amount of water per capita is next to be con-
sidered. This depends somewhat upon the habits of
the people as to the use of water for domestic purposes,
and for watering lawns and streets; somewhat upon the
amount of water sold now or likely to be sold for manu-
facturing, railway, and trade purposes; and still more
upon the amount of water that is wasted by takers and
the amount lost by leakage from the pipes.
The present consumption we will say is 100 gallons
per capita daily. A greater manufacturing use is to be
anticipated, but on the other hand, it is proposed to in-
stall more meters upon the services which will reduce
the waste. This will offset the increase in actual use per
capita, and we will consider 100 gallons per capita daily
as the probable consumption ten years hence.
The quantity of water to be provided is thus 100 gallons
per capita for a population of 100,000, or 10,000,000
gallons per day.
Ten million gallons per day is the average daily
Il8 REQUIRED SIZES OF FILTERS, ETC.
amount for the year. Sometimes the use will be less
and sometimes more than the average. There are few
cities where the maximum month does not exceed the
annual average by 15 per cent. There are some where
it is 50 per cent greater. In this case 25 per cent is
assumed.
The maximum monthly consumption will thus be 25
per cent above the average, or 12,500,000 gallons per
day.
The maximum daily consumption must be taken as
10 per cent more than this figure, or 13,750,000 gallons
per day.
During some hours of the day the rate of consump
tion is far greater than at other hours. The excess of
the maximum hourly rate over the average daily rate is
more nearly in proportion to the population supplied
than it is to the average amount of supply. In other
words, the use of water fluctuates, while the waste does
not fluctuate, and where waste is large in proportion the
fluctuations expressed in percentage of the whole are
less. In this case a rate of 80 gallons per capita is taken
as representing the excess of maximum rate of consump-
tion over the average of 100. The maximum rate of
use, therefore, will be at the rate of 180 gallons per capita,
or 18,000,000 gallons per day.
This does not include the water required for fire ser-
vice, which must still be added. For ordinary fires
which are quickly put out, no very heavy drafts are
made. But for the larger fires, which occur at long
intervals, a liberal supply must be furnished.
In this case, taking into account the nature of the sit-
MAXIMUM RATES OF DRAFT. II9
uation and value of the property, we assume that water
to supply 30 standard fire streams should be available.
Such streams use 250 gallons of water per minute, or at
the rate of 360,000 gallons per day for each fire stream.
Thirty streams will require water at the rate of 10,800,000
gallons per day.
If this was added to the maximum rate of use, 18,000,000
gallons per day, it would give the extreme maximum rate
to be provided for of 28,800,000 gallons per day.
Actually there is so little probability of the occurrence
of the maximum fire at precisely the time of the maxi-
mum use of water for other purposes that we can aflFord
to take a few chances on it, and this figure may be cut
somewhat. With an average use of 100 gallons per
capita, rates exceeding 130 gallons per capita would not
occur for more than a small percentage of the time.
This would be 13,000,000 gallons per day. Adding our
30 fire streams, or 10,800,000 gallons per day, to this,
we have 23,800,000, or say 25,000,000 gallons per day,
as the amount which the works must be capable of sup-
plying when there is demand for it in case of a heavy fire.
It is only necessary to prepare to supply water at this
highest rate for three or four hours, but the works must
be able to supply water at the maximum daily rate of
i3)75o>ooO) or say 14,000,000 gallons per day, when
required, for a number of days in succession.
We can now take up the sizes required for the different
parts of the works.
If an impounding reservoir and its catchment area
are sufficient to maintain a constant supply in a dry
year equal to the annual average contemplated use, that
I20 REQUIRED SIZES OF FILTERS, ETC.
will suflSce. The reservoir will take care of fluctuations
in the rate of draft, and no computation need be made
of the efiFect of such fluctuations.
The pipe line leading from the impounding reservoir
to the distributing reservoir near the city must have a
capacity equal to the maximum daily use of 14,000,000
gallons per day, or 40 per cent above the average annual
use
The hourly fluctuations will be balanced by the dis-
tributing reservoir. The storage capacity required to
balance the fluctuations of ordinary use will be about
15 per cent of the average daily use or 1,500,000 gallons.
In addition to this, enough capacity to maintain the
maximum fire draft for four hours should be added. This
will require:
^ (25 — 10) =2,500,000 gallons capacity.
24
This makes the required capacity of the distributing
reservoir 4,000,000 gallons per day.
It is not usually convenient to so operate a plant as to
keep the distributing reservoir always full, and a fire
might occur when it was somewhat drawn down. To
provide for this a further allowance should be made,
bringing the capacity to 5,000,000 gallons, or one-half a
day's average supply. And if the fire risk is large, the
site suitable, and the financial conditions warrant it, a /
larger reservoir, up to at least a full day's supply, will be
safer and better.
Purification works and pumps, if used, located between
the impounding reservoir and the distributing reservoir,
must have capacities equal to the maximum day's use,
SIZE OF DISTRIBUTING RESERVOIR. 121
and, in addition, reserve units or capacity must be pro-
vided to cover the time lost in cleaning filters and in re-
pairing pumps; and it is customary to have a reserve unit
of each kind, so that the supply would not be crippled
by having one pumping or filtering unit out of service
for some time.
As a general rule, where the distributing reservoir
balances hourly fluctuations and provides for fire service
requirements, the filters should have a capacity a half
greater than the average rate of consumption, and the
pumps should have a nominal capacity twice as great as
the average rate of pumping.
The average rate of the filters will thus be two-thirds
of the maximum rate, and the pumping machinery will
operate equal to one-half its nominal capacity when the
capacity of the plant is reached. At all other times the
ratio of use to capacity will be less.
The pipes from the distributing reservoir to the city,
and through it, must have a capacity up to the maximum
rate of use of 25,000,000 gallons per day.
If the water is pumped from the reservoir to the city,
the pumps must have this capacity with one unit in
reserve. This means practically that the pumps for
direct service must have a capacity equal to three times
the average rate of use. In small works the pumps
must be even larger than this in proportion.
It never pays to build filters and purification works to
meet the maximum rate of consumption. Even in case
of a river supply and direct pumping of the filtered water
into the distribution pipes, it pays to provide a pure water
reservoir at the filters to balance the hourly fluctuations
122 REQUIRED SIZES OF FILTERS, ETC
in rate. This permits the purification plant to work at
a constant or nearly constant rate throughout the twenty-
four hours, which is advantageous.
The figures used in this illustration are representative,
but there are reasons in particular cases why higher or
lower values must be used. But in every case there are
certain ratios that must be met. With pumps capable
of lifting 10,000,000 gallons per day, and filters capable
of filtering, and pipes capable of carrying this quantity,
it has never been possible, and it never will be possible,
to deliver under the required conditions of practical ser-
vice 10,000,000 gallons of water per day, nor even an
approximation to this amount.
This matter, although very simple, is mentioned at
length because it is one of the most common matters to
be misunderstood, and a perfectly clear understanding
of it is essential.
Some most important projects have been seriously
defective and incapable of their supposed capacities be-
cause of inadequate allowances of this kind.
CHAPTER XII.
AS TO THE PRESSURE UNDER WHICH WATER IS
TO BE DELIVERED.
In considering source of supply, the question of the
elevation of the source and of the distributing reservoir
is often an important matter, as it concerns the pressure
imder which water is or might be supplied.
In the older American water works only very moderate
pressures were used. In New York, Boston, Philadel-
phia, Washington, and a hundred other cities the works
were laid out so that with reasonably satisfactory piping,
water was available in the highest stories of the houses
that were common at that time, or, in a general way, in
houses three or four stories high. The works were fur-
ther generally arranged to maintain this pressure only
in those parts of the cities which were comparatively low
in elevation, those parts at the time ha\dng contained
most or all of the houses for which public supply was
regarded as necessary.
The elevation of the reservoir once fixed for a certain
service and pressure, it is by no means an easy matter
to change it, and the elevation and pressure thus estab-
lished many years ago have been in most cases main-
tained to the present day, even though the conditions
have so far changed that if new works were now being
laid out, the arrangements made would certainly be very
diflFerent from the actual ones.
123
124 WATER PRESSURE.
Occasionally where new or additional works are laid
out, there is an opportunity to change the conditions
in this respect. Such change nearly always involves
the abandonment of some old structures, especially
reservoirs that are too low for the new conditions;
and sometimes old pipes not strong enough to stand
the new pressure. Changes in pumping stations
may also be involved, or the construction of new
ones.
The reasons for and against such changes must be
carefully weighed. But in many cases the old condi-
tions are so thoroughly inadequate, that radical and
expensive changes are desirable and necessary.
The tendency of the times is clearly to the use of much
higher pressures.
Higher pressures are desirable for a number of rea-
sons, among them the following:
(i) Buildings are in general much higher than a
generation ago. Practically all of the higher buildings
in the above mentioned cities, and in many others, find
it necessary to install pumps to lift the water to tanks on
their roofs, from which the supply in the building is
maintained. In New York City alone many thousands
of buildings are obliged to maintain their own pumping
plants and tanks. The aggregate cost of installing
these private supplementary works, and of operating
them, is very large. If the city could increase the water
pressure in the mains so as to make these private works
unnecessary, this cost would be saved to the citizens,
and the saving so made would probably greatly exceed
the cost of increasing the pressure of the public supply,
I
HIGHER PRESSURES NEEDED. 125
even though that involved, as it would, many new, exten-
sive and costly works.
(2) Cities in growing have extended to higher land
than that originally occupied, and for such higher areas
the service is particularly deficient. In many cases such
higher areas are left to get on as best they can with the
pressure that is available. When they are so high that
such service is entirely inadequate, separate high service
systems have usually been installed. That is to say,
such areas are supplied by an entirely separate system
of pipes, and water is pumped or otherwise supplied to
them at a higher level or under greater pressure than is
used in the main service.
Many areas are so high above the lower part of the
cities that separate high service districts are really nec-
essary, but there are many other cases where the areas
could be supplied satisfactorily from the main service if
the pressures in the older and lower parts of the cities
were increased to the points which would be most advan-
tageous for them on their own account. In general, it
is best to keep the pipe systems as simple as possible, and
to avoid separate high service systems where the service
to the higher districts can be reasonably maintained in
another way.
(3) Higher pressure is desirable for fire service; that
is to say, for use in putting out fires. There are very
wide differences in the capacities of diflferent water
works systems for this use. In European water works
practice, owing principally to the less inflammable
nature of the buildings, but little provision is made for
fire service. The water pipes are provided to distribute
126 WATER PRESSURE.
the water from the source to all the points where it is
taken, and in the quantities needed for ordinary require-
ments. Some provision is made for anticipated growth,
and allowance is made for fluctuations in rate occurring
in the diflferent hours and minutes of the day; but in
general the pipes are small in size, especially the lateral
pipes, which arc often as small as four, three, and even
two inches and less in diameter.
Some early American water works were laid on this
plan, but it is to be found now in general only in small
villages which have grown very slowly, most of them
having spring water supplies. Such supplies do not
furnish much fire protection. Buckets of water may be
obtained to put out a starting fire, but no effective fire
stream from a hose can be obtained to put out a fire
already under way.
The first step in providing fire service is to arrange
the pipes so that a supply of water to fire engines or
pumps can be obtained from them. To do this requires
the provision of a reservoir or pumps to deliver water to
the pipes at a greatly increased rate in case of fire, and
increasing the sizes of the pipes above the sizes required
for ordinary service to such an extent that the required
quantity for fighting a fire in addition to the usual flow
can be taken from hydrants in any part of the city.
This result is more easily obtained where pipe lines
are cross-connected into a *' gridiron system," as is now
customary. By this means every pipe is reinforced
within a reasonable distance by a number of other pipes,
and the quantity of water that can be drawn from it is
correspondingly increased. With the fire engine system
FIRE PROTECTION. 1 27
no efiFort is made to supply water for fire service under
pressure sufiicient for direct use without fire engines, and
there is therefore no need of raising the pressure on the
whole system because of the fire service to be obtained
from it. The pressure required to throw streams of water
on to the fire is all obtained from steam fire engines con-
nected with the hydrant or hydrants nearest to the fire.
Years ago four-inch pipe was laid in water works
systems, to be used in this way; but this proved inade-
quate in practice, and the minimum size now used is six
inches in diameter. In New York City, the minimum
size now laid is eight inches, and in districts of large,
inflammable buildings the minimum size is still larger.
This arrangement, with modifications here and there, is
in use in Boston, New York, Philadelphia, Washington,
and most of the older cities supplied by gravity from
reservoirs, at relatively low elevations.
The next step in fire protection is that kno^^^l some-
times as the Holly system. This is used only for sup-
plies which are pumped, and is commonly used in the
smaller cities of the Middle States. Pumps are provided
of a capacity greatly in excess of the ordinary use, and
built to produce a pressure much beyond that needed for
ordinary service. Ordinarily the pumps are operated
slowly, and only a moderate pressure is maintained.
Extra boilers are kept with steam up, and in case of an
alarm of fire the pump is at once speeded up to give an
extra volume and an extra pressure. The pressure is
commonly increased to the point where the hose can be
attached to hydrants and good fire streams obtained
directly from them without the use of fire engines to
128 WATER PRESSURE.
further increase the pressure. A pressure of 70 pounds
per square inch at the hydrant is regarded as about the
minimum for this service, and to secure this, even in per-
fectly flat country, a somewhat greater pressure at the
pumping station must be carried to cover the loss of head
by friction in the pipes. Pressures of one hundred pounds
and over are common. More pressure is needed if the
buildings to be protected are large and high. In this
system the pump at the water works station does the
work that would otherwise be done by the fire engines.
This system works well in small towns where fires do
not occur often. In large cities, with frequent fire
alarms, the disturbances from fluctuating pressure would
be too great, and the system is not used.
At Chicago, Detroit, etc., where direct pumping and
no reservoirs are used, the increased rate of draft is taken
care of by the pumps, but no effort is made to increase
the pressures during fires so as to allow direct fire streams
to be used. Fire engines are always used to give the
additional pressure required.
The next step in giving more fire service is the main-
tenance at all times of pressure in the pipes high enough
for fire service. When this is done, every fire hydrant is
just as good as a fire engine up to the capacity of the pipes.
This system has been adopted, especially with gravity
sources of supply high enough in elevation to maintain
such a service without pumping. Such supplies are often
in hilly country, and the pressures in different parts of
the area served may vary greatly. Full fire service may
be maintained on the lower levels, and less adequate
service supplemented by fire engines may be used on the
FIRE PROTECTION.
129
higher levels. As the largest buildings are usually upon
the lower levels, this arrangement works very well.
Among the cities having such comparatively high pres-
sure are the following:
Place.
Extreme maxi-
mum pressure^
pounds
Maximum
pressure over
a considerable
area, pounds.
Ordinary mini-
mum pressure,
pounds.
Fitchburg .
Syracuse . . .
Westfield .
Springfield
Worcester . .
Newark . . .
Peekskill. .
Kingston . .
Fall River . .
Providence . ,
t * t
170
ICX)
• • •
120
170
• • •
140
130
120
• •
"5
100
125
• • •
iS8
• • •
• • •
114
75
60
65
35
70
• • •
158
80
65
There are some disadvantages of high pressure, real
and supposed:
Where the water is pumped, the cost of pumping is
increased. This is a question of cost, and the cost can
be computed.
Increasing the pressure tends to a greater waste of
water. If all the openings remained the same, the water
waste would increase as the square root of the average
pressure. Multiplying the pressure by four would in-
crease the waste by two. For a comparatively small
increase, adding two per cent to the pressure would add
one per cent to the amount of waste. Actually the in-
crease of waste is not in this proportion, for leakage
from a pipe under higher pressure makes more noise and
is more easily discovered than leakage from a pipe under
I30 WATER PRESSURE.
lower pressure, and it is therefore more likely to be
discovered and stopped.
Formerly there may have been difficulty in providing
pipes and plumbing to stand successfully as high pres-
sures as may now be considered. But there is no trouble
in securing pipes and fixtures to do it now. An increase
in pressure may be somewhat destructive of some old
plumbing, but pressure reducers can be put on to indi-
vidual houses to avoid this with considerable success;
and in any new work the additional pressure is not
objectionable, and does not increase the cost of properly
designed plumbing. Better work is required, but the
sizes may be smaller.
In recent years a great many cities have installed spe-
cial high pressure services for fire use These are usu-
ally entirely independent of the ordinary water supply,
and they are mentioned here briefly only for complete-
ness. In several cases salt water is used for this service.
Otherwise, river or lake water is taken at the nearest
point, regardless of quality. Pressure is only kept up
when needed.
In other cases the high pressure water is from the same
source as the ordinary supply, and the fire pressure may
be constantly kept upon the special pipes if it is a gravity
supply. This last arrangement has the advantage of
allowing especially high buildings to be supplied from
the high pressure pipes, and it is not unusual for the
same system of pipes that supplies extra pressure down-
town to extend to and supply at ordinary pressures parts
of the city upon higher land. In other words, the pipes
from a high service district are simply extended through
FIRE PROTECTION. 131
a low service area having special need of high pressure
water. Newark, Worcester, Fitchburg, and other cities
have this arrangement.
American cities are built in a way to make them more
subject to damage by conflagration than those of any
other country. The abundance of wood in the past,
and the cheaper construction with it as compared with
other building materials have had much to do with this.
There has also been far too little attention paid to build-
ing in a way to make serious fires impossible.
Most of the buildings now being erected are better in
this respect. Each modern steel building, with fire-
proof walls and floors, erected in place of an old building
with wooden floors, reduces the chance of conflagration.
A bad fire cannot start in such a building; and if one
starting outside burns to it, it tends to act as a barrier to
the fire and stop its progress.
With rebuilding going on at its present rate, the fire
conditions in our cities will improve, until ultimately the
requirements of fire service upon the water works system
will be reduced to an approximation of what they now
are in European cities. That is to say, it will only be
necessary to provide pipes for the distribution of water
for ordinary purposes, with a comparatively small addi-
tion for fire requirements.
But that day is a long time in the future. At the pres-
ent time we are using vast numbers of buildings that are
anything but fire-proof. These buildings on the whole
are good and useful, and must continue to be used for
many years; and so long as they remain, water works
systems must be plaimed and built and used to protect
132 WATER PRESSURE.
them. The property that may be lost in a day through
failure of water in a San Francisco or Baltimore fire will
pay for very generous additions to the pipes and pumps
and reservoirs in many cities.
Under present conditions there can be no doubt that
far better fire protection would pay in many or most
American cities, and it is well worth while to secure it.
But the certain ultimate improvement in building con-
ditions, that is to say, the gradual elimination of .fire-traps
and the substitution of buildings that are fire-proof, or
nearly so, must be kept in mind in planning for works to
serve for long periods.
CHAPTER XIII.
ON THE USE, WASTE, AND MEASUREMENT OF
WATER.
The quantities of water supplied in a number of Amer-
ican cities are as follows :
Place.
Pittsburgh .
Bufifalo . .
Philadelphia
Washington
Chicago . .
Detroit. . .
Boston . .
Cleveland .
New York .
Newark . .
Milwaukee .
Minneapolis
Worcester .
Providence .
St. Paul . .
Hartford . .
Lowell
Fall River
Year.
Gallons
per capita
daily.
1905
250
1900
233
1905
1906
227
218
1900
190
1905
190
1905
15^
1905
137
1902
129
1900
94
1905
1904
91
82
1900
1905
1900
1906
70
68
67
63
1905
52
1905
37
Percentage
of services
metered.
I
2
• •
3
3
29
6
68
35
21
94
42
94
86
28
100
69
97
The quantities of water supplied in a few European
cities are as follows:
»33
134 USE, WASTE, AND MEASUREMENT OF WATER.
Place.
Year.
U.S.
Gallons
per capita
daily.
Place.
Year.
U.S.
Gallons
per capita
daUy.
London . .
Liverpool .
Paris . . .
Amsterdam.
1906
1902
190I
1905
39
65
37
Berlin . .
Hamburg .
Dresden . .
Copenhagen
1905
1905
1905
1905
22
44
26
27
And in Australia
Place.
Year.
U.S.
Gallons
per capita
daily.
Place.
Year.
U S.
Gallons
per capita
daily.
Melbourne.
Sydney . .
1905
1905
63
39
Brisbane
1906
58
Taking it right through, probably one-half the water
supplied to American cities is wasted. Some of this
waste is unavoidable, but the greater part of it could be
stopped.
Because of this great waste of water the cost of the
works is increased, and likewise the cost of maintaining
them.
The increase in cost is not as rapid as the increase in
quantity of water, but it is substantial. Probably the
whole cost of supplying water in America is from a third
to a half greater than it would be with the reasonable
suppression of waste. In some cases the ratio is much
greater.
If the policy of Philadelphia and Buffalo is to be fol-
lowed in allowing everyone to take and waste water as
freely as he likes without paying for it, then the source
of supply and other parts of the works must be provided
GREAT WASTE OF WATER 1 35
with a capacity four times as great as where the policy of
Worcester and Hartford, of making each one who draws
water pay for the amount drawn, is followed.
The advantages of putting a meter on each service and
collecting water rates according to its indication are so
great and so obvious to all w,ho have studied the water
question, that this system promises to become universal
in America at no remote date.
When this happens such preposterous conditions as
securing and pumping at great expense 250 gallons for
each man, woman, and child of the population, of which
amount four-fifths, more or less, is lost by leakage ab-
solutely without benefit to anyone, will cease to exist.
On the other hand, it must not be forgotten that in
America water is a relatively cheap commodity, and it is
likely to remain so, and people will not limit themselves
closely in its use. Wealth is increasing; we live in larger
houses, have more bath tubs and other fixtures and
use them oftener; generous lawns and wide streets need
water to keep them presentable, and at fair prices it can
be easily afforded.
Let our aim be a generous use of water, but no waste,
and each man to pay for what he gets.
It is idle to attempt to ascertain what the per capita
consumption for any city in the future will be. To fore-
cast it roughly for a few years is all that need be done or
can be done. The water resources of the country are
enormous, and they must be developed gradually as there
is need of them, and it is the clear duty of the water
departments and water companies to develop them as
they are needed.
136 USE, WASTE, AND MEASUREMENT OF WATER.
In some cases where unrestricted waste has been per-
mitted, large reductions are possible by changing the
methods of sale; but in many other cases there will be
increases as people use more water and are willing to
pay for it. It is clear that per capita consumptions as
low as those in some European cities are not to be antici-
pated or desired in America. The tendency is the other
way. The European figures are steadily increasing, even
where all water is sold by meter.
Meter Rates and the Sale of Water. Much of the un-
fortunate and ignorant opposition to the use of meters
has been caused by unreasonable and unjust methods of
charging for the water passing the meters. There has
been the greatest diversity in these methods of charging,
but the underlying principles that should govern are
being slowly worked out, and improvements in schedules
of charges for metered water are slowly but surely being
made by the water departments of the country.
The price at which any commodity is sold will nor-
mally be found between two limits. It will not be less
than the cost to the seller to produce and deliver, nor will
it be greater than the value or utility of the product to
the buyer. Water is a commodity and its price is gov-
erned by these limits. When the works are owned by a
city there is a strong tendency to ignore the second limit
and to reduce the price to the first hmit, or in other words
to sell the water at cost.
In general, this tendency will control, but it does not
seem necessary that it should do so to the exclusion of
other considerations in all cases. One man gets more
comfort or makes more profit from a thousand gallons
METER RATES AND THE SALE OF WATER. 1 37
of water than his neighbor. If the difference can be
ascertained and measured, there would seem to be no
reason why it should not be taken into account in fixing
the rates. Of course, the practical difficulty is in ascer-
taining such differences, and this difficulty will greatly
limit the use that can be made of the relative value of
the service to the taker, but in some cases use may be
made of it.
It may be noted that manufacturers and railroads are
not slow in representing to water departments that their
business will not stand existing rates, or that other sup-
plies can be more cheaply obtained, and on such grounds
asking for reductions in charges. And these reductions
are frequently made usually because the business is
needed, and is acceptable to the water department even
at a reduced rate. On the other hand if a water depart-
ment renders a service which is especially and unusually
advantageous to someone, as often happens, there would
seem to be no reason why a charge should not be made
greater than where only the usual benefits result from
the service.
This matter aside, the problem presented is briefly
this: a certain quantity of water is dispensed for all sorts
of purposes, and a certain sum of money is to be raised
to meet the needs of the department. How can the
takers be most fairly taxed to produce the required
revenue or a reasonable approximation thereto?
In the first place, the amount to be raised is to be
divided into two parts, namely, a first part, including all
expenses and capital charges, the amounts of which are
dependent upon the amount of water supplied; and a
138 USE, WASTE, AND MEASUREMENT OF WATER.
second part, including all other charges and expenses,
which are those not dependent upon the amount of water
supplied.
This di\'ision can be made only approximately. Mak-
ing it is a question for the accountants, and the different
items in the total schedule of payments made in a year
must be carefully looked over to see how far each would
be affected by a change in the quantity of water supplied.
There will be plenty of room for discussion as to many
of the items, and only a rough approximation need be
attempted. It may even be made arbitrarily by assum-
ing that one- half or one- third of the total expense is not
affected by the quantity of water supplied.
Having separated our schedule into these two parts
the first part is to be taxed upon the water according to
volume; the second part is to be taxed upon the fixtures
and property according to rules to be adopted.
If all the water went through meters, and if the meters
recorded it all, the first sum divided by the quantity of
water supplied in a year would be the rate that would
have to be charged for all water to produce the required
revenue; and there would seem to be no adequate reason
for, nor justification of, a sliding scale as it is called, that
is, of a schedule by which small takers pay more in
proportion than large ones.
The calculation has sometimes been made in this way,
when only a part of the water has been metered, but it
will not work out with all the water metered, and for this
reason it is unjust when only a part of it is metered.
There are two reasons for this: first, some water is lost
by leakage from the pipes before the meters are reached
COMPUTATION OF METER RATES, 1 39
and never passes through them; and second, the meters
practically always pass more water than they record.
When water passes a meter rapidly it is recorded with
considerable accuracy, but when it flows through slowly
some of it leaks around the moving parts, and the amount
registered is below the truth. This is especially the case
with meters that have been worn by use, and the meters
of a city, as a whole, register a smaller proportion of water
passing them than is shown by the usual shop tests of
meters even when these tests are made at low rates of flow.
Meters wear less rapidly when the water is perfectly
clear filtered water or ground water than where river and
other surface supplies are used.
Under present American conditions it does not seem
possible to make the meters account for more than from
50 to 70 per cent of the supply. This shortage does not
all come from the slip of the meters. Some of it is from
the leakage from pipes.
There is reason to believe that the proportion of water
accounted for will be gradually increased with better
conditions. Some German cities do much better than
this in accounting for their water at the present time;
If the amount that can be accounted for is not kno'WTi
by actual experience for the works in question, then the
calculations should be made on the basis that 60 per cent
of the water, or thereabouts, will be actually charged for,
and that this amount will produce the full sum to be
raised in this way.
The assessment of the second part of the amount to be
raised, that is to say, the part that is not affected by the
amount of water that is used, presents greater difl5culties.
I40 USE, WASTE, AND MEASUREMENT OF WATER.
In studying this division two thoughts should be kept
in mind. First, the amount charged in this way on each
ser\dce should not be less than the sum that will serve to
maintain the service and the meter upon it and pay the
cost of reading the meter and of the proper proportion of
the bookkeeping and general expenses which are in no
way affected by the amount of water that is used.
Second, the amount to be raised in this way may, with
propriety, be charged to some extent, according to the
value of the service to the taker, as far as that can be deter-
mined by a simple and sure method of calculation. All
property is more valuable because a good water service is
available and quite apart from the amount of water that
is used, and there is no reason why some payment should
not be made to the water department because of this
element of value in the service.
The simplest way of apportioning the sum to be raised
in this way is to divide it equally among the services.
Berlin, Germany, collects twelve marks, equal to about
three dollars per annum, for each service, and in addition
collects payment for all w^ater recorded by the meters.
Milwaukee has similarly collected one dollar per annum
for each service, but this is clearly too low a figure. It
will not pay for the maintenance of the services and
meters.
A better way is to base the payments upon the size of
the service. Most of the services of a svstem are domes-
tic services, that is to say they serve residences. These
services are commonly five-eighths of an inch in diameter.
The assessment on these may be placed at $2.00 per
annum, let us say. Some takers insist on a larger ser-
CHARGE FOR SERVICES. 141
vice because they wish to draw water more rapidly.
Many discussions take place because the prospective taker
is insistent on a larger service, while the water works
superintendent believes the usual size to be sufficient.
Why not let the taker have a service as large as he likes
and charge him for it in proportion to its size, or, let
us say, approximately in proportion to its ability to
deliver water ?
Starting with a charge of $2.00 for a five-eighth inch
service, and using round figures, the charge for larger
services, not including the charge for water would be
For i-inch $3 00 per annum
For i-inch 6.00 "
For i}-inch 12.00 '* "
For 2-inch 22.00 " **
For 3-inch 48.00 " "
For 4-inch 85.00 " "
For 6-inch 192.00 " "
For 8-inch 340.00 ** "
This arrangement has the practical advantage of
making a substantial charge for a substantial service,
and for a service that too often is not adequately paid for,
where large pipes lead from the mains into mills, ware-
houses, etc., for fire purposes only, and from which
pipes ordinarily no water is drawn.
These pipes cause more trouble to water departments,
and the privileges granted are subject to more gross
abuse, than those from any other class of service; and it
is right and proper that substantial payments should be
made for them.
Such large fire services should always be metered
and they should not be allowed to exist on any other con-
dition. This has not been possible imtil recently, but
142 USE, WASTE, AND MEASUREMENT OF WATER.
it can be done now, for a type of meter has been invented
which is satisfactory from a water works standpoint, and
which does not interfere materially with the value of the
pipe for fire ser\ice. With this meter the water ordi-
narily passes through a by-pass on which there is a small
meter. But in case of need, that is in case of fire, a valve
on the main line opens automatically and the full quan-
tity of water that the pipe will carry flows through it
unobstructed for use. Even in this dase an approximate
idea of the amount of water drawn is registered by some
extremely ingenious devices which are only brought
into play when the main valve is opened.
The general idea of charging in proportion to the
areas of the service pipes has been expressed in the form
of minimum rates at Cleveland and other places. I do
not know that it has been followed anywhere to its logical
conclusion, as above outlined.
Another way to divide the sum to be taxed on ser-
vices is in proportion to fixture rates. This method is
applicable especially in cities which are gradually chang-
ing from fixture charges to the meter system. In this
case the fixture rates are kno\^Ti for each house. Sup-
posing it is decided to assess one-third of the whole
amount to be raised upon fixtures then when a meter
was installed on a given service the charge for that ser-
vice would be one-third of the previous fixture rate, and
in addition all water used would be charged for.
For these conditions this system has much to recom-
mend it. But it is a transition system. When all ser-
vices are metered it is not to be supposed that it will be
worth while to continue making fixture rates. A more
OTHER CONSIDERATIONS. 1 43
simple method of computation will be demanded and
should be used. This can be brought about without
the slightest trouble, and without any radical change
when all services are metered.
In England the charge for water is commonly based
on the rental value of the property supplied. People
li\ang in expensive dwellings pay more for their water
than those li\-ing in cheaper ones. It would not be
unreasonable in fixing the amounts to be assessed on
fixtures to take into account either the rental value or
the selling value of the properties; but this idea so far as
I know has never found expression in American sched-
ules. In New York and a few other cities the width and
height of the house are taken into account, but not the
value.
There is another point that might be taken into ac-
count with reference to fire service. Water works cost
more to build and maintain because there are so many
inflammable buildings requiring large volumes of water
instantly available for their protection in case of fire.
Other buildings are being erected in rapidly increasing
numbers, so little inflammable that only small volumes of
water arc needed for their protection. Why should fire-
proof buildings pay as much as fire-traps toward the
excess cost of the service?
It might not be possible to apply this to domestic ser-
\aces, but it certainly could be applied to connections
made specially for fire purposes. If the price computed
in proportion to areas is taken as the standard, and ap-
plicable to slow-burning well protected mill construction,
then why not reduce the charge to one-half for thoroughly
144 USE, WASTE, AND MEASUREMENT OF WATER.
fire-proof buildings, and double it for old and dangerous
buildings? Or within certain limits the charges might
be based upon the fair insurance premiums paid on fully
insured property.
There are so many considerations that might fairly be
taken into account that it will be found impossible to
make a schedule recognizing all of them and at the same
time sufficiently certain and simple to be satisfactory in
practice. For a schedule of rates must be easy and cer-
tain in application, readily understood by the public as
well as by the registrar, and it must not be frequently or
arbitrarily changed.
Practically the best way to handle the matter is to
devise a schedule based on calculations of the general
nature indicated above, and computed to yield a revenue
of lo per cent more than is actually required. This
excess allowance is made because there is always some
uncertainty as to the effect of changing rates upon the
revenue to be produced; and it is better to raise some-
what too much revenue rather than to fall short.
This schedule should be simple and certain, and all
figures should be expressed in round numbers. For
instance, if the calculation came that way, the figures
given in connection with the different sized services
might be used and in addition seven cents per thousand
gallons for all water used. If this was estimated to
yield lo per cent more revenue than required, there
would be a chance of falling below expectations by this
amount without embarrassing the department, while
under other conditions the revenue might exceed that
required by 20 per cent or more.
THE SLIDING SCALE. 145
In the case of an excess of revenue being demonstrated,
the charge for water could be reduced to six cents or to
five cents as the business would stand, or the charge
for services might be lowered. Practical experience
with the general method would be available to indicate
where the cuts could be best and most equitably
made.
The use of a sliding scale, that is to say, or making
lower rates to large takers, is firmly fixed, and it will
be hard to do away with the idea. But the writer
believes that such a scale as that suggested contains
all the provisions of this kind that are necessary or
wise.
In the first place this kind of a scale is in reality a
sliding one. The small cottage pays, let us say, $3 per
year for the service, and in addition uses water charged
at $0.10 per 1000 gallons, let us say, amounting to $3 per
year in addition. The total payment is $6 per year and
the average cost of water to the taker is $0.20 per 1000
gallons.
A larger taker pays, let us say, $12 per year for his
service, and uses at the same rate water worth $120 per
annum. The whole bill is then $132 and the average
cost of water to him is $0.11 per 1000 gallons, against
the $0.20 paid by the smaller taker.
The basing figures of course are to be fixed to meet
local conditions, and when so fixed they will give all the
slide that is desirable. There is no reason why the man
in a cottage, who lets his plumbing get out of order and
wastes an extravagant quantity of water, should be asked
to pay a larger price per thousand gallons for the water
146 USE, WASTE, AND MEASUREMENT OF WATER.
wasted by his neglect than is paid by the largest estab-
lishment.
Manufacturers are often supplied by cities at special
rates which are less than cost. This is most frequently
done on special pleas, and is comparable to giAing exemp-
tion from taxation. The practice is not a wise one and
should not be encouraged.
Low rates are also often made to secure customers who
would not otherwise use water or who would not use so
much. This is most apt to be done in the early days of
operation of a system when the capacity of the works built
in anticipation of growth is beyond present requirements.
Hydraulic elevators and motors are most common and
objectionable subjects for such special rates. As long
as the capacity of the works is really in excess of the
demand, a little financial help is received by the depart-
ment from such rates; but as soon as the capacity of
the plant is af>proached such rates become a drag and
a source of loss. Experience shows that they are not,
and cannot possibly be shut oflf promptly when they
cease to be profitable. It is, therefore, better and safer
to charge the regular rates for water used for these
and all other special purposes, and to take good care
that all water so used is paid for. Some revenue
will be lost; some elevators and printing presses will
be driven by electricity instead of by water power,
but electricity is a better way of transmitting power
than water under pressure, and in the end all will be
better oflf.
American cities having high service systems make
precisely the same charges for water from them as for
CHARGE FOR HIGH SERVICE WATER. 147
water from the low service pipes. The man on the top
of a hill with high service water pays no more than the
man in the valley, though to supply him costs the city
usually from two to five cents more per thousand gallons,
and where the high service districts are small and iso-
lated the extra cost may greatly exceed these figures.
There seems to be no well-founded reason for this
equality in charge with clearly defined difference in
cost of service.
It would seem rational and wise to charge more for
high service water than for low service water, and to
establish the differential carefully at so many cents per
thousand gallons, to pay as nearly as it can be computed
for the additional cost of the high service water; and the
differential should be subject to revision from time to
time as the conditions of service change. Usually it
would be higher at first, with few takers, and less as the
quantity sold became greater.
The present method is unfair to those on low ground.
They pay their share (usually the largest share) of the
excess cost of supplying water to those located on the
hills. And this is the more unfair, as the hill sites are
usually more desirable for residences, and those who live
on them are well able to pay the added cost which their
service entails on the water department.
I have described this meter rate question at some
length, because I feel strongly that present methods of
charging are in general unfair and unreasonable, and
because I believe that the adoption of the general prin-
ciples here outlined will do a great deal to improve the
situation.
148 USE, WASTE, AND MEASUREMENT OF WATER.
The sooner arbitrary and unreasonable methods are
abandoned, and more reasonable methods are adopted,
the better it will be for both consumers and for water
departments, and the easier it will be to supply clean
water and to make the financial arrangements for
doing it.
CHAPTER XIV.
SOME FINANCIAL ASPECTS.
In America water works receipts average about $2.50
per capita for the population supplied, but figures rang-
ing all the way from $2.00 to $4.00 are common, and
some figures are outside of this range. These are for
publicly owned works. Private companies average to
make about the same collections for domestic rates, and
in addition they are paid for fire service, so that their
total receipts average about $3.00 per capita. Publicly
owned works as a rule receive no separate payment for
fire protection.
There seems to be no well marked tendency to either
higher or lower collections per capita in the larger cities,
as compared with the smaller ones. Large cities usually
have to go farther for water. Small sources near at
hand are not available to them, and it would seem rea-
sonable to suppose that the relative cost would be greater.
But it seems that the savings which are made by operat-
ing on a larger scale offset this tendency, and on the
whole, the expense of securing water is just about the
same on an average in proportion to population in small
cities and in large ones.
In Europe the per capita cost of water is rather less.
In London where the works of eight private companies
were turned over to public ownership in 1903, and where
149
ISO SOME FINANCIAL ASPECTS.
the rates charged by the companies continue practi-
cally without change, the collections amount to $2.00 per
capita, which does not include any separate payment for
fire service.
Paris collects about $1.50 per capita, and this seems to
be also about the average amoimt collected in English
cities, excluding London, under public ownership. In
other European cities, as far as returns are available, the
collections do not average more than about $1.50 per
capita.
In Australia the collections seem to be nearly up to
the American average. But little fire service is provided,
but the population supplied is scattered, necessitating
rather great length of distribution piping. The per
capita quantities of water supplied are not high, but the
cost of securing the water is relatively high.
In arid districts the per capita cost of water works may
be increased almost indefinitely with the increase in
value of the water to the takers and in the cost of
securing it.
In comparing American with European conditions, it
must be remembered that, in general, a much larger
expenditure has been made in Europe for the purpose of
improving the quality of the supplies, and, on an aver-
age, the qualities of tho waters actually supplied show
the effect of this expenditure and are better than Ameri-
can waters. On the other hand, the American works
have been built at considerable additional cost to enable
them to supply water rapidly in case of fire, a condition
which, in general, does not exist in Europe because of
the less inflammable character of the buildings; and
EUROPEAN CONDITIONS. 151
the additional cost of the larger pipes and reservoirs to
meet this condition in America may be as much as the
additional expenditures for quality in Europe.
Labor is cheaper in Europe, but probably the number
of men employed is enough greater to offset the effect of
the lower wages paid.
The principal element of difference is in the quantity
of water supphed. American cities on an average prob-
ably use two or three times as much water per capita as
European cities, or, more correctly, they waste so much
as to produce these ratios in the amounts supplied. It
certainly seems reasonable that to supply two or three
times as much water per capita the cost of the service
would be increased by 60 per cent.
The disposition of the $2.50 per capita collected on an
average in America is about as follows: First, in works
where the supply is from a gravity source, and no purifi-
cation is used, about $0.50 per capita annually is used
for paying the general expenses of administration, of
taking care of services, meters, etc., of making repairs,
and of maintaining the works generally. The $2.00
remaining pays 4 per cent interest, and i per cent depre-
ciation, or together 5 per cent capital charges on a cost
or value of works averaging $40 per capita. The $40 is
about equally divided between the distribution system,
which includes the pipes in the streets of the city, the
services, meters, etc., and the source of supply, which
includes all the works for securing the water and bring-
ing it to the city.
Second, in works where the supply is pumped from a
river or lake near at hand, with or without purification,
152 SOME FINANCIAL ASPECTS
about $0.50 is used for the general expenses as above
mentioned. Another $0.50 is used for pumping and
purification (rather more when the water is purified; less
when it is not); and the remaining $1.50 pays 5 per cent
capital charges on an average investment of $30 per
capita, of which $20 is in the distribution system and $10
in the source of supply.
Gravity sources of supply cost more to secure, but are
cheaper to operate.
The above mentioned figures are general approxima-
tions, given to show general water works conditions in
America at the present time, but wide fluctuations will
be found in individual cases.
Some cities are so located that no good, adequate
source of supply is near at hand; and where water is
brought from long distances and is pumped and purified,
it is clear that it cannot be delivered at the cost or sold
at the price that is fair for a water drawn from a pure
and ample source near at hand.
Then the cost of distribution differs. In a city on
level ground where one service or one system of pipes
does for all, the cost both of construction and of
operation is less than on a hilly site where separate
high service districts must be maintained, involving
additional pipe systems and additional pumping stations.
And a city that is compactly built up, so that it
can be served with a pipe system having a mile
or less of pipe per thousand of population, can be
more cheaply served than a scattered city with long
lines of pipe running out where there are but few
houses, and where, taking it right through, two or
THE VALUE OF PURE WATER. 153
even three miles of pipe are required per thousand of
population.
Cities that waste large amounts of water have to pay
for it. The cost of the works is greater, and this cost is
sure to be represented sooner or later in the assessments.
Matters of these general natures largely explain why
some cities can be supplied for less than $2 per capita
while others must collect over $4 per capita.
The service of water is one of the cheapest. The aver-
age American family pays far more for gas, for ice and
for milk, than for water. In my own household in New
York, taking the cost of Croton water at $1, the average
cost of other household supplies is as follows: Ice $3,
Light $4, Telephone $5, Coal $13, Milk $15. Taking
into account the nature of the water service, which has
become absolutely indispensable, the low cost is very
remarkable.
Rather than not have it, a city like New York could
afford to pay without hesitation ten times the present
water rates; and such rates would be paid if there was
necessity for them, as happily there is not, and never
will be.
Some interesting computations indicating the enor-
mous value of pure water to the inhabitants of a city have
been recently pubUshed.^ I shall not repeat them here,
but will only call attention to one well known and highly
significant fact. When the inhabitants of an American
city get the idea, rightly or wrongly, that the water of the
public service is not good to drink, many of them pro-
ceed to supply themselves with drinking water in other
» The Value of Pure Water; G. C. Whipple ; John Wiley & Sons.
154 SOME FINANCIAL ASPECTS.
ways. Filters of greater or less 'efficiency are installed
in thousands of houses, and bottled spring waters find
an extended sale at prices which represent handsome
profits to the venders. Such sales of spring water may
be brought about by the turbidity of the water, or by its
color, or by tastes and odors, or by iron in it, or by de-
ficiency in hygienic quality, and the supposition, often
well founded, that disease may be produced by it.
It is difficult or impossible to ascertain even approxi-
mately how much money is spent for spring water; but
in some cases partial returns of a reliable nature indicate
that the payments for spring water by the relatively
small number of people who can afford it, are equal to
twenty per cent or more of the gross revenue of the water
department. This ratio of expense for spring water prob-
ably is not uncommon in American cities, and there are
probably some cases where it is greatly exceeded. In
the homes of the wealthy the spring water bill may be
many times larger than the charge for the water of the
public supply.
I cite this condition merely to show the value which
that part of the public which can afford it puts on good
water, as measured by its willingness to pay cash for it.
Now there is hardly a city in America supplying bad
or inferior water at the present time which could not
substitute a new supply, or purify the present one, no
increase of quantity being made, at a total cost repre-
senting less than twenty per cent of the water rates; and
in many cases' this could be accomplished for ten per cent
of those rates, or even less. And this is with reference
to a new or improved supply so free from hygienic
STANDARDS OF PURITY. 155
objections, turbidity, color, and all other objectionable
qualities, that there would be no reason left for resorting
to spring water.
Such a standard of purity is clearly within the reach
of all cities at this time. There is no good reason
why a lower standard in any particular should be
accepted.
And in many of our cities an amount of money suffi-
cient to bring the whole public supply .to this standard,
if it were so applied, is spent by the relatively small num-
ber of well-to-do people who can, or think they must,
afford it for spring water, which spring water is not of
better quality, and is often of far worse quality, than that
to which the public supply for all the people might rea-
sonably be brought.
It is imnecessary to develop this matter further.
There is no uncertainty about it. Only one conclusion
can be reached. The American people ought to have
for their public supplies water substantially equal in
hygienic quality and in physical appearance and attrac-
tiveness to the best spring water. Such supplies can be
secured. Sometimes water of this quality can be se-
cured naturally; at other times by artificial purification.
The means to be used for accomplishing this end are well
known. The costs of carrying them out are reasonable.
The advantages of pure water are worth far more than
the cost of securing it.
The service of water to the public as the business is
now conducted is a very cheap one. The people could
afford if necessary to pay far more than they now do
for good water; but fortunately in most cases no great
156 SOME FINANCIAL ASPECTS.
increase in the cost of the service need be made to
secure it.
There is not the slightest doubt that the American
people will more readily and cheerfully pay $4 per capita
for an adequate ser\ice of pure, attractive water than
they will pay $2 for an inferior service, while the differ-
ence m cost of maintaining the ser\dce will never be as
great as this.
Under these conditions the plain duty of the water
departments and of the water companies of the country
is, first, to provide a thoroughly adequate service of pure
water and of attractive water; and second, to fix the
water rates so that this service can be paid for by them.
At the present time there are many laws, ordinances,
debt limits, and bonds outstanding, which limit action
and prevent the immediate following of this policy.
But where there is a general determination to secure a
result, it can be reached, and a better understanding of
the conditions by those who make and repeal the laws
and ordinances, and are responsible for other arrange-
ments, is the first step in bringing about the desired
conditions.
CHAPTER XV.
THE LAYING OUT AND CONSTRUCTION OF
WORKS.
The amount of money invested in water works in the
United States at this time, 1907, is probably not less than
$800,000,000, and the true value of the properties prob-
ably exceeds largely this figure. The amount of money
spent on new construction, either in new projects, or in
the development and enlargement of old ones, is cer-
tainly not less than $30,000,000 per year, and this amount
is increasing.
Of this, one-half or less is for ordinary extensions of
pipes, for instalhng meters, etc., and the rest is for new
sources of supply, new pumps, and new purification
worksj and for the enlargement of old ones.
As a rule men do that best which thev are accustomed
ft
to do, and that which they do frequently; they do less
well or even badly the things that they have not done
before. It looks easy enough to swim, or to fit a coat,
or to play a piano; but we know that there is little pros-
pect of success in doing these things in the first attempt
of the novice.
It is much the same with cities in the building of water
works. The work that is done frequently and regularly
is done well, often extremely well; and that which is
undertaken but seldom, or for the first time, is very apt
157
IS8 LAYING OUT AND CONSTRUCTION OF WORKS.
to be badly managed; and many misfit coats are worn
M-ith as good a grace as possible because the wearer does
not Mish to admit that he did not know how to cut his
ovm coat. It may even be that he does not yet know it
to be a misfit.
Most water works departments lay their own water
pipes and ser\-ices and set their oiMi meters. That is to
say, they do these things with their own men, and not by
contract. As a rule the men employed are honest, intel-
ligent and faithful. Practice of neighboring cities is
studied and improvements are readily adopted. As
a rule these men become skilfull as well as faithful,
and their work is well done, and on the whole it is
cheaply done.
The work done in this way represents at least a third
of the whole construction account, and for it the
departments usually secure full value for the money
expended.
So far as they do not, it is mostly due to failure to pro-
vide and work to a sufficiently comprehensive general
plan. A six-inch pipe is put down this year in a street
where a ten-inch will be required five years hence; and
when this happens the value of the six-inch first laid will
have largely disappeared. Such losses can be almost
entirely prevented by making a general plan of pipes
suitable for the city after some years of growth, as nearly
as that growth can be foreseen, and thereafter laying all
pipe in accordance with it. Much money can be saved
in that way in comparison with that which is spent imder
the too common system, or rather lack of system, where
such pipes arc put down each year as will relieve those
WASTES IN CONSTRUCTION. 159
deficiencies of the system which then appear most
pressing.
But the wastes from badly advised piping are trifling
when compared to those on other parts of the construc-
tion work. This is because the departments are not
used to laying out new works and building them. These
things are required but seldom in any one city, and those
ha\nng to do with one such installation are seldom on
hand for the work of building the next one. If they
were, their experience in many ways would have lost its
value, owing to the progress of the art in the interval.
The study of recent works of neighboring cities is often
relied upon, and if rightly used it is most helpful. But
occasionally it is the reverse, where local conditions do
not permit of copying. Storage reservoirs are built,
where the need is rather for more catchment area tribu-
tary to the works; large distributing reservoirs are built,
where smaller ones at higher levels, or more pumps or
purification works would be far more useful; and types
of construction useful in one place (or not, as the case
may be) are cheerfully copied, where they are not suit-
able, and where the money could be better laid out in
other constructions.
Certainly the sources of supply in i\merica, taking it
right through, cost a fourth more than they would cost
if the methods of procedure that are well known and
tried and adapted to the service were used in all cases.
Putting it in another way, the savings that could be
reasonably made in water works construction by better
management and by better engineering certainly amount
to several millions of dollars per year in the United
l6o LAYING OUT AND CONSTRUCTION OF WORKS.
States. And this does not include any allowance for
savings to be made by new inventions and methodSi
which would largely add to this figure.
These possible savings represent a fund that may be
di\dded between the people (in reduced water rates)
and the engineers and superintendents and managers (in
increased fees and salaries) who have the ability to bring
the improvements about.
The public does, and always will, get most of the sav-
ings to be made in this way; but there is plenty of chance
for men of ability and training to make great savings,
and to receive generous compensation for doing it, and
it is for the best interests of all that such services should
be secured by the water departments and be adequately
paid for by them.
Some cities and water companies have for many
years made special eflorts to secure such services, and
the superior character of their works, and the increased
values which they have obtained for their expenditures,
are very clear to the few who take the trouble to inquire
carefully into these matters.
On the other hand, some of our largest cities spend
fifty per cent more on their works than is necessary, and
sometimes even a hundred per cent more. Some do
even worse than this. They build expensive works that
on any rational theory of development they do not want,
and cannot use to advantage.
Some of this is due to incompetent engineering advice.
More of it is due to lack of ad\dce or to failure to act
upon it when it is obtained.
There is much more that might be written upon this
UNNECESSARY EXPENDITURES. l6l
subject. It might be shown how in some lines of work
the development is so rapid that even the most recent
text-books are hopelessly out of date; how the subjects
are becoming so complex that only the principles and not
the important details can be treated in them; how the
most efficient works are designed by groups of men, each
attending to the parts which he best understands, and all
under the general direction of a chief who has a clear
idea of the end to be reached and the way of reaching
it, though he may know less of many of the details than
his subordinates; how the only way to learn a business is
to be brought up in it, and how it cannot be learned by
a casual inspection from the outside.
There is a strong temptation to develop some of these
ideas, but it must not be done in this place. The writer
is too directly interested in this business. To take up
these matters would be too much like blowing his own
horn, or at best, that of his profession. And besides,
the water departments are steadily finding out the truth
about these matters, and it is better that they should
reach it in their own way.
At this point I wish to record a tribute to the many
faithful, earnest, unpaid, or but slightly paid, men serv-
ing on water boards, and water committees, who have
conscientiously studied the water problems of their cities
and the best ways of sohing them, and have stood for
the right, even against strong but ignorant, or misin-
formed public opinion, and have in this way secured for
the cities which they have served water supplies far better
than would otherwise have been possible. I have known
hundreds of these men, working year after year for the
1 62 LAYING OUT AND CONSTRUCTION OF WORKS.
good of their cities, entirely without compensation, and
too often without thanks. Sometimes I have had an in-
sight into what effort it has cost them. More often I
have realized in some measure the value of their services
to the commimities in which thev live.
It is this feature of our municipal life, too often for-
gotten or unknown, which must increase, as I believe it
will, until it controls and excludes the baser elements.
All honor to the men who quietly and without show do
their full duty in the public ser\dce!
The water works superintendents also deserve a word,
for they are among the hardest working and most poorly
paid of men. With telephones in their residences they
are on duty twenty four hours a day and seven days in
the v/eek. Vacations are few and short. All routine
work usually goes through their hands, and very often,
when thev are stronger and better informal than their
boards or committees, they practically determine the
policy to be followed on all important matters. And, as
a rule, the superintendents are right. As a rule they are
not men of broad training, and often they miss the main
chance, but on the whole, things are far more apt to go
right when the superintendent's suggestions are followed,
as they are pretty apt to be. Considering the conditions
of service, it is surprising that the superintendents, as a
class, are as efficient as they certainly are.
For the future it is to be hoped that the business will
be made more of a profession; that the salaries paid will
be larger; and that more men of broad technical training
will be enlisted in the service.
CHAPTER XVI.
ON THE FINANCIAL MANAGEMENT OF PUBLICLY
OWNED WATER WORKS.
Under this heading I shall not attempt to describe the
methods in actual use in American cities for financing
their publicly owned water works. These methods are cer-
tainly varied and in many cases have admirable features.
I propose here to bring together those methods and ar-
rangements which seem particularly suitable, and then
to make a financial scheme, ideal and visionary, to the
extent that no city is following it throughout, but practical
and tried, to the extent that most of its individual features
are in successful use in one or another American city.
Likewise no treatment of the management of works by
private companies is intended, though the plan outlined
for city management follows closely, as it should, the
arrangements that are suited to company management,
with only one important point of difference: That is, that
a company has properly for its end the payment of di\d-
dends, while the object of publicly owned works is to
give as good service as possible, and to assess the cost of
it as fairly as it can be done, both between the different
takers at the present time, and between those of to-day
and those of the years that are to come, during the period
for which financial arrangements now made will be in
operation.
163
1 64 FINANCIAL MANAGEMENT.
The method to be here outlined is intended to secure
this result as fairly as possible and with a minimum of
trouble and inconvenience. It is more complicated than
the methods now used by many water departments, but
perhaps not more eleborate than is necessary to reach the
desired results. For the methods of bookkeeping used by
many water departments do not give a clear idea of their
financial situation nor whether the present arrangements
are leading to bankruptcy or to an imusually large
surplus, unless the tendency is very strong.
This is often the case. Water departments collect
more than is really needed, because of ignorance as to
true conditions; but this tends to good service, and at
worst only means that the present generation is paying
the water bills of a future one in some measure. The
opposite condition of too low collections is fortunately
less common, though it has been followed by many cities.
In the end it is far more disastrous to have the rates too
low than too high.
In developing this proposed method a number of
definitions will be necessary.
The True Value of a water works property as a whole
is the fair market value of the property, including all real
estate, rights of every kind, and structures, valued as if
the present owners wished to sell, and as if a party at
hand was desirous of buying and operating it. The case
of the transfer of the works from private to public owner-
ship may be assumed as the one for which there are most
precedents, but transfer from one company to another,
and from the city to a company may also be consid-
ered.
VALUE OF WORKS. 1 65
In general, it will be fair to assume that the franchise has
expired and that no special allowance is to be made for
it, though in some cases, as when a city has just con-
demned works with a valuable franchise for which it has
paid, this would be unfair and the franchise value should
be included. A going concern value, or a value for the
fact of having actual connections and an established
business, in comparison with a plant otherwise complete,
but with a business yet to be acquired, may fairly be
allowed.
The Appraised Value is an approximation to the true
value, made at a given time by the water department, or
for it, to be used as a basis of calculation. The methods
of appraisal of water works properties need not be dis-
cussed here. Such properties are frequently valued by
arbitration, or by court proceedings, for the purpose of
fixing the sale value from a company to a city, or else for
the purpose of serving as a basis for fixing the water rates
which may be charged by a company. The principles
of water works valuation have been ably discussed, and
many lawyers and engineers have had extended experi-
ence in their application.
The Book Value or capital account is the value of the
plant as a whole as used for the purpose of bookkeeping
and computation. It may be arrived at in a number of
ways, but most frequently by taking the book value of
the preceding statement and adding to it all moneys spent
since on construction, and substracting all allowances
to be made for depreciation. The book value is to be
kept as nearly as may be to the appraised value. This
can be controlled by the amount marked off for depre-
1 66 FINANCIAL MANAGEMENT.
ciation, and the depreciation should be adjusted to a
simple schedule, to produce the required result as nearly
as can be estimated. New appraisals may be made
once in five or ten years, and the depreciation allowance
increased or decreased as necessary to preserve an ap-
proximate equality.
The Bonded Indebtedness is the whole outstanding
bonded obligation, less the sinking fund if there is one.
Water works are generally paid for by cities in the first
place by money raised on bond issues, and if the value
equals the cost when first built, then the bonded indebt-
edness equals the value of the plant. But such a condi-
tion does not last. Usually with plants long in operation,
and bonds partially paid off, the bonded indebtedness is
far below the fair value of the property.
The Citys Equity is the book value of the plant, less
the bonded indebtedness. This corresponds to the
stock value of a plant owned by a company. This
equity I would treat exactly as if it were stock. Its
ownership, vested in the city government as trustee for
the citizens, gives the right to control the works, and a
fair rate of dividends on its value should normally be
earned by the operation of the plant.
The Construction Account must be rigidly separated
from the operation account, and must show all money
spent for new works and for additions.
The Operation Account must include all receipts and
expenses in the normal operation of the works, includ-
ing all interest payment on the bonds, and all other pay-
ments in the way of returns, on the invested capital,
and the allowance for depreciation.
OPERATING ACCOUNT. 167
The principal items that will go to make up the opera-
tion account are as follows:
Receipts: (i) the water receipts from all private
consumers. This is the principal part of the income,
and the methods of collecting it now in use are usually
good and adequate.
(2) Receipts for water supplied to other city depart-
ments. The bills for such services should rest on meter
measurement, should be made up at the same rates as
would be charged to private takers for the same services,
and should be promptly collected in all cases; and other
city departments using water should be authorized and
required to pay for it out of their appropriations, and
when necessary those appropriations should be increased
to cover this item. Only a few American cities have
followed this practice. Most of them have supplied
water without charge to other city departments. And
the water departments have had to pay dearly for this
generosity. For other city departments receiving water
without cost and without hmit are the most incorrigible
wasters of water. The loss of water, which is equivalent
to loss of revenue, and to increased operating expenses
to keep up the supply, is a direct hardship on the water
departments. Further, the loss is not limited to the
direct loss. The example of public waste of water is
irreconcilable with demands for private suppression of
waste, and the public is not slow to see the point and act
on it.
The only adequate way to stop this abuse is to meter
the water to each department and collect for it at current
rates from the appropriations for that department.
1 68 FINANCIAL MANAGEMENT.
It need only be suggested that no successful com-
mercial or manufacturing business is operated without
making charges between diflferent stores, factories and
departments, and the necessity for such charges is cer-
tainly not less in city business.
(3) A collection from the city for hydrants and water
for fire protection. Private water companies always
charge for this service. Some publicly owned works
also charge for it, but most of them do not. The charge
should be made in all cases, but the rate of charge may
be fixed at as low a figure as will cover the additional
expense of maintaining hydrants, and the excess capaci-
ties of the pipes needed to make them eflfective. It is
impossible to make a close computation of the fair
charge for this service, but a reasonable approximation
may be reached.
The rate of charge might appropriately be higher
where a pressure sufficient to give fire streams direct
from the hydrants is maintained, that is to say for hy-
drant pressures of seventy pounds and over; and lower
where the pressure is so low as to be only effective when
increased by the use of steam fire engines.
There will be some minor collections, but substantially
these three items will make up the gross revenue, and
the rates charged must be adjusted from time to time
to produce the required income.
The payment side of the operating account will be
made up principally of these five items:
(i) Operating expenses, including all salaries, general
expenses, costs of pumping, protecting catchment areas,
maintaining mains, services and meters, special engi-
OPERATING ACCOUNT. 16^
neering and other professional advice, and, in short, all
current expenses of every sort.
Space in city buildings not owned by the water depart-
ment should be paid for at current rates for rent, and
all services rendered by other city departments should
be paid for, and the amounts included under this
heading.
(2) Interest on all bonds outstanding. Usually there
is no indebtedness outside of the bonds issued for con-
struction, but if there is any other the interest payments
upon it should be included in this item.
(3) Taxes on the works, assessed precisely as if the
works belonged to a private company. Water works at
present pay taxes on those parts of their works located
outside the city limits to those towns, etc., in which they
are located, but often under special rules of assessment
made by the state legislatures, limiting the assessments
to sirnis far below the full values of the properties. Hol-
yoke has set the admirable example of taxing also the
parts of the works in the city on the same basis as' other
property, and this example is worthy of being invariably
followed. The basis of assessment should be as nearly
as possible that followed on private property. There
should be no attempt to unduly reduce the assessment.
There is enough tax dodging, and the city which suflFers
from it should set a good example.
The reasons for leaving many forms of city property
without taxation do not apply to water works property.
It is conmiercial and profitable property, and is no less so
because it belongs to the city, and it should be treated
accordingly. School and university property is usually
I70 FINANCIAL MANAGEMENT.
exempt from taxation as long as used directly for educa-
tional purposes; but as soon as a revenue is derived from
any part of it (even though that revenue is used for edu-
cational purposes) that part becomes taxable. This rule
is just, and it should be applied to water works property.
(4) A group of charges, calculated on diflferent theo-
ries, but all serving the same general purpose, including
sinking fund payments, depreciation allowances marked
oflF from the capital account and charged to the operating
account at the end of the year, and all payments for
renewals except minor renewals, paid out of operating
expenses.
The amount to be paid into sinking funds is often
established by law or by the provisions of the bonds; the
amount paid for renewals is easily ascertained; but the
amount allowed for depreciation is a far more difficult
matter to arrive at. Its regulation ultimately depends
upon the principle that it is to suffice to keep the book
value and the true value as near together as possible, and
time only will show whether the amounts assumed and
used are adequate. In the meantime an approximation
must be made and used, and modified whenever the
experience already accumulated shows clearly that the
charges that have been used are either too high or too
low. At the outset it is better to allow too much for
depreciation than too little.
When the whole cost of the works is represented by
outstanding bonds, on which sinking fund payments are
established, such payments alone may be sufficient or
even excessive, and no further depreciation allowance
need be made.
DEPRECIATION ALLOWANCE. I/I
The allowance also may properly be less as more
extensive and thorough renewals are made, thus keeping
up the value of the property.
A general increase in the value of real estate and of
the cost of building will make the works more valuable
and reduce temporarily the need for a depreciation allow-
ance, while the reverse condition will increase it. The
allowance will also be less where the works are designed
wisely with reference to future growth, so that but little
will have to be discarded as the years go by, and as all
parts of the plant are carefully looked after and protected.
The care of the mains to prevent deterioration resulting
from stray currents of electricity from trolley-cars (called
electrolysis), for instance, would tend to reduce deprecia-
tion, and lack of attention to it might greatly increase it.
It is apparent that anything like a close computation is
impossible. It is my feeling, based on the examination
of a number of old works, and on estimates and compu-
tations relating thereto, that for most American water
works an annual allowance of one per cent of the value
of the property for all the charges coming under this
item will suffice.
In some cases half this charge would no doubt suffice.
With increasing values of real estate some works would
stand no allowance at all for a time, but this should never
be taken as a permanent basis. On the other hand,
with badly designed works, or with sources of supply
near the limit of their usefulness, either because of in-
sufficient quantity or unsatisfactory quality, so that the
early abandonment of parts of the works must be con-
templated, charges of two or three per cent, or more,
172 FINANCIAL MANAGEMENT.
might be required until a better and more permanent
basis was reached.
(5) The payment of dividends on the stock, or on
the city's equity in the property. The practical opera-
tion of the water works in New York, Philadelphia,
Pittsburgh, and many other cities, results in the realiza-
tion by the city of a certain return (and often a large one)
on its investment in the works, but in no case is such
a plan systematically and adequately carried out. In
many cities the opposite principle is followed. The
city's equity in the works is deliberately overlooked,
and no payments are made on account of it.
The city's equity may be the result either of money
raised by taxation and invested in the works, or of sur-
plus profits from operation, which have been accumu-
lated by the department. In the former case there
can be no possible reason why the city should not
receive a reasonable return on its investment. In the
latter case it may be urged that as the accumulation is
made up of water profits it should be used for the benefit
of water takers; or, in other words, it is held that water
should now be sold for less than actual cost because in
the early years of operation it was sold for more than
cost, and it is held that the accumulation from the profits
of the early sales must be dispersed, and lost to the city.
The writer believes that it is fairer and more business-
like to regard the past as a closed chapter; to take mat-
ters as they stand; to find out the true cost of supplying
water under present conditions as nearly as it can be
ascertained, that cost including interest on all the money
invested in or represented by the present value of the
AS TO THE PROFITS. 1/3
plant, regardless of whether the equity now owned by
the city has been produced by money raised by taxation
or from surplus profits of the works themselves.
The management of the matter by the city may follow
that which would be followed by an individual in man-
aging a company for the benefit of the stock which he
o\vned in it, with only this limit, that it may be supposed
that the city only cares to make a moderate dividend
rate, and will reduce the water rates whenever it can do
so without reducing the dividend rate too low. In years
of bad business it will reduce dividends or pass them.
With good business, fair dividends will be paid, and the
average dividend through a term of years may reason-
ably be kept somewhat greater than the rate of interest
which is paid on the bonded indebtedness. The extra
rate is to cover the element of risk in the business, and
corresponds to the extra rate that there must be a chance
of earning to make such a business attractive to a
private investor.
As to the disposition of the dividends received by
the city, the first use would be naturally to take up new
stock to pay for additions to the works. It is clearly
wise to do this, and the money so contributed for con-
struction purposes would render unnecessary a corre-
sponding amoimt of bonds. And this policy would
increase the profits to the city from the business as its
equity in the works increased.
In rapidly growing works, and where the city's equity
at first was small, all dividends for many years could be
wisely reinvested in the works; but ultimately a large
net revenue to the city above the requirements for new
174 FINANCIAL MANAGEMENT.
construction would result from this policy, and this
revenue might be dedicated, if desired, to providing
libraries and hospitals and parks, or any other public
works not of a productive nature.
The general policy thus outlined, if adopted, would
place publicly owned works on the basis of privately
owned works in all respects but two; namely, th3 interest,
apart from dividends, in giving the best possible service,
and the absence of desire to earn more than a fair rate of
interest on the capital invested. And these .two reasons
are precisely the reasons for public ownership, and they
are substantially the only reasons for it. In all other
respects the management should be the same in both cases.
The publicly owned works should have the benefit of all
the collections that a company could make in its place,
and it should be subject to all the charges that a company
would have to pay.
The comparison with a company is convenient and
helpful, but the real reason for the adoption of these
methods is not that they are used by companies, but
because they are sound business, and would be equally
desirable if there were not a water company in existence.
Their use will lead to the sale of water to evervone at
actual cost, as nearly as that cost can be determined, and
no one ought to expect to get water cheaper; and it will
result ultimately in the ownership by our cities of splendid,
safe, revenue-producing properties.
And the ownership of such properties will be doubly
gratifying when they supply clean water.
INDEX.
Page
Action of Iron on Color loi
of Water on Iron Pipes 59
Advantages of Natural Lake for Reservoir 27
Aerating Devices 90
Aeration to Remove Tastes and Odors 92
Appraised and Book Values of Water Works 165
Ashokan Reservoir 5
Boston Water Supplies 5
Catchment Areas, Care of 11
Catchment Areas, Reservoirs Partially Connected with ... 6
Catskill Water Supply 4
Charge for Services 140
Coagulating Basins 89
Devices 89
Coagulation, Methods of 77
Coloring Matter, Fermentation of 99
Color in Reservoir Waters 24
Color in River Waters 39
Computation of Amount of Storage Required 9
Computation of Meter Rates 138
Consumption, Maximum Rates of 118
Copper Sulphate, Use of 23
Croton Works, City of New York i
Driving Wells 47
Fermentation of Coloring Matter 99
Filter Galleries 46
176 INDEX.
Paqx
Filters in Use So
Mechanical 87
Filtering Water, Kirkwood's Plan for 67
Financial Aspects, Some 149
Financial Management of Public Water Works 163
Fire Service 126
Flushing Pipes 65
Ground Water from Sand and Gravel Deposits 43
Iron in 5a
Supplies, Sea Water in 56
Ground Waters, Hardness of 50
Manganese in 55
Growths of Organisms, Odors and Tastes from 18
Hardness of Ground Waters 50
Hyatt Patent Filter 77
Hygienic Efficiency 109
Standards of Purification no
Impounding Reservoirs in the West 8
Principal Use of 3
Influence of Population on Quality of Water 13
Intermittent Filtration 95
Iron and Line Process of Treating Water 76
Iron in Ground Water 52
on Color, Action of loi
Pipes, Action of Water on 59
Tuberculation in 60
Kirkwood's Plan for Filtering Water 67
Lake for Reservoir, Advantages of Natural 27
Lawrence Filter, The 71
La)dng Out and Construction of Works 157
Limestone Water 48
Limits of Purification 113
Louisville Experiment 73
INDEX. I jy
Page
Manganese in Ground Waters 155
Maximum Rates of Consumption 118
Mechanical Filtration 93
Meter Rates and Sale of Water 136
Computation of 138
Methods of Coagulation 77
of Purifying Water . . . ! 82
Odor and Tastes, Accumulation of 17
from Growths of Organisms 18
Pipe Scrapers 62
Principal Use of Impoimding Reservoir 3
Process of Purification 82
Pumping, Reservoirs with 7
Public Water Works, Financial Management of 163
Pure Water, Value of 153
Purification of Sewage 34
Purifying Water, Methods of . 82
Rainfall and Runoff Records 9
Relation of Water Supply to Sickness and Death 33
Reservoir, Advantages of Natural Lake for 27
Waters, Color in 24
Reservoirs for Filtered Water 114
Partially Connected with Catchment Areas 6
River Water Supplies, Sanitary Aspects of 33
Waters, Color in 39
Sale of Water, Meter Rates and 136
Sand and Gravel Deposits, Groimd Water from 43
Sand Filters 78, 88
Filtration 94
Sanitary Aspects of River Water Supplies 33
Scrubbers 86
Sea Water in Ground Water Supplies 56
Sedimentation ^
1/8 INDEX.
Pagx
Sewage and Water Supply 29
Purification of 34
Sickness and Death, Relation of Water Supply to ^s
Size of Distributing Reservoir 121
Sizes of Filters, etc 117
Softening 106
Stagnation of Water in Impounding Reservoirs 14
Storage, Cumputation of Amount Required 9
Straining 85
Stripping 21
Tastes and Odors 92
Aeration to Remove 92
Temperature of Water 15
Tuberculation in Iron Pipes 60
Turbidity 37, 102
Unnecessary Expenditures 151
Use of Copper Sulphate 23
Use, Waste and Measurement of Water 133
Value of Pure Water 153
Wachusett Reservoir 6
Wastes in Construction 159
Water from Lime-Containing Materials 51
Influence of Population on Quality of 13
in Impounding Reservoir, Stagnation of 14
Pressure 123
Purification in America 67
Supply and Sewage 29
Works, Appraised and Book Values of 165
Wells in Sandstone Rock 46
West, Impounding Reservoirs in the 6
UN!V. OF MICHIGAN,
NOV 25 19U
Short- TITLE Catalogue
OF THE
PUBLICATIONS
OF
JOHN WILEY & SONS
New York
London: CHAPMAN & HALL, Limited
ARRANGED UNDER SUBJECTS
Descriptive circulars sent on application. Books marked with an asterisk (♦) arc
sold at net prices only. All books are bound in cloth unless otherwise stated.
AGRICULTURE— HORTICULTURE— FORESTRY.
Armsby's Principles of Animal Nutrition 8vo, $4 00
* Bowman's Forest Physiography 8vo, 5 00
Budd and Hansen's American Horticultural Manual:
Part I. Propagation, Culture, and Improvement 12mo, 1 50
Part II. Systematic Pomology l2mo, I 50
Elliott's Engineering for Land Drainage 12mo, 1 50
Practical Farm Drainage. (Second Edition, Rewritten.) 12mo, 1 50
Graves's Forest Mensuration. . . .' 8vo, 4 00
* Principles of Handling Woodlands Large 12mo, 1 50
Green's Principles of American Forestry 12mo, I 50
Groten felt's Principles of Modem Dairy Practice. (Woll.) 12mo, 2 00
* Herrick's Denatured or Industrial Alcohol 8vo, 4 00
Holm's Milk in Denmark. (In Press.)
* Kemp and Waugh's Landscape Gardening. (New Edition, Rewritten.) 12mo, 1 50
* McKay and Larsen's Principles and Practice of Butter-making 8vo, 1 50
Maynard's Landscape Gardening as Applied to Home Decoration 12mo, I 50
Sanderson's Insects Injurious to Staple Crops 12mo, I 50
Insect Pests of Farm, Garden, and Orchard. (In Press.)
* Schwarz's Longleaf Pine in Virgin Forest l2mo, 1 25
* Solotaroff's Field Book for Street-tree Mapping 12mo, 75
In lots of one dozen 8 00
* Shade Trees in Towns and Cities 8vo, 3 00
Stockbridge's Rocks and Soils 8vo, 2 50
"Winton's Microscopy of Vegetable Foods 8vo, 7 50
WoU's Handbook for Farmers and Dairymen 16mo, 1 50
ARCHITECTURE.
Atkinson's Orientation of Buildings or Planning for Sunlight. (In Press.)
Baldwin's Steam Heating for Buildings 12mo, 2 50
Berg's Buildings and Structures of American Rarilroasds 4to, 5 00
1
Allen's Tables for Iron Analysis 8vo,
Armsby's Principles of Animal Nutrition. . ; 8vo,
Arnold's Compendium of Chemistry. (Mandel.) Lar, e 12mo.
Association of State and National Food .and Dairy Departments, Hartford
Meeting, 1906 8vo,
Jamestown Meeting, 1907 8vo,
Austen's Notes for Chemical Students 12mo,
Baskerville's Chemical Elements. (In Preparation.)
Bemadou's Smokeless Powder. — Nitro-cellulose, and Theory of the Cellulose
Molecule 12mo,
* Biltz's Introduction to Inorganic Chemistry, (Hall and Phelan.). , . 12mo,
Laboratory Methods of Inorganic Chemistry. (Hall and Blanchard.)
8vo,
* Bingham and White's Laboratory Manual of Inorganic Chemistry. . 12mo.
* Blanchard's Synthetic Inorganic Chemistry 12mo,
Bottler's Varnish Making. (Sabin.) (In Press.)
* Browning's Introduction to the Rarer Elements 8vo,
* Butler's Handbook of Blowpipe Analysis 16mo.
* Claassen's Beet-sugar Manufacture. (Hall and Rolfe. ) 8vo,
Classen's Quantitative Chemical Analysis by Electrolysis. (Boltwood.).8vo,
Cohn's Indicators and Test-papers 12mo,
Tests and Reagents 8vo,
Cohnheim's Functions of Enzymes and Ferments. (In Press.)
* Danneel's Electrochemistry. (Merriam.) 12mo,
Dannerth's Methods of Textile Chemistry 12mo,
Duhem's Thermodynamics and Chemistry. (Burgess.) 8vo,
Eff rent's Enzymes and their Applications. (Prescott.) 8vo,
Eissler's Modem High Explosives 8vo.
* Fischer's Oedema 8vo,
* Physiology of Alimentation Large 12mo,
Fletcher's Practical Instructions in Quantitative Assaying with the Blowpipe.
16mo, mor.
Fowler's Sewage Works Analyses 12mo,
Fresenius's Manual of Qualitative Chemical Analysis. (Wells. ) 8vo,
Manual of Qualitative Chemical Analysis. Part I. Descriptive. (Wells.)8vo,
Quantitative Chemical Analysis. (Cohn.) 2 vols 8vc,
When Sold Separately, Vol. I. f6. Vol. II, $8.
Fuertes's Water and Public Health 12mo,
Furman and Pardee's Manual of Practical Assaying 8vo,
* Getman's Exercises in Phy.sical Chemistry 12mo,
Gill's Gas and Fuel Analysis for Engineers 12mo,
* Gooch and Browning's Outlines of Qualitative Chemical Analysis.
Large 12mo,
Grotenfelt's Principles of Modem Dairy Practice. (Woll.) 12mo,
Groth's Introduction to Chemical Crystallography (Marshall) 12mo,
* Hammarsten's Text-book of Physiological Chemistry. (Mandel.) 8vo,
Hanausek's Microscopy of Technical Products, (Winton. ) 8vo,
* Haskins and Macleod's Organic Chemistry 12mo,
* Herrick's Denatured or Industrial Alcohol .,, 8vo,
Hinds's Inorganic Chemistry 8vo,
* Laboratory Manual for Students 12mo,
* Holleman's Laboratory Manual of Organic Chemistry for Beginners.
(Walker.) ■ 12mo,
Text-book of Inorganic Chemistry. (Cooper. ) 8vo,
Text-book of Organic Chemistry. (Walker antl Mott.) 8vo,
Holley's Analysis of Paint and Varnish Products. (In Press.)
* Lcail and Zinc Pigments Large 12mo,
Hopkins's Oil-chemists' Handbook 8vo
Jackson's Directions for Laboratory Work in Physiological Chemistry. .8vo,
Johnson's Rapid Methods for the Chemical Analysis of Special Steels, Steel-
making Alloys antl Graphite Large 12mo,
Landauer's Spectrum Analysis. (Tingle.) 8vo,
Lassar-Cohn's Application of Some General Reactions to Investigations in
Organic Chemistry. (Tingle.) 12mo,
Leach's Inspection and Analysis of Food with Special Reference to State
Control 8vo,
Lob's Electrochemistry of Organic Compounds. (Lorenz.) 8vo,
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Lodge's Notes on Assaying and Metallurgical Laboratory Experiments.. 8 vo,
Low's Technical Method of Ore Analysis 8vo,
Lowe's Paint for Steel Structures 12mo,
Lunge's Techno-chemical Analysis. (Cohn.) 12mo,
* McKay and Larsen's Principles and Practice of Butter-making 8vo,
Maire's Modem Pigmwits and their Vehicles 12mo,
Mandel's Handbook for Bio-chemical Laboratory 12mo,
* Martin's Laboratory Guide to Qualitative Analysis with the Blowpipe
12mo,
Mason's Examination of Water. (Chemical and Bacteriological.) 12mo,
Water-supply. (Considered Principally from a Sanitary Standpoint.)
8vo,
* Mathewson's First Principles of Chemical Theory 8vo,
Matthews's Laboratory Manual of Dyeing and Textile Chemistry 8vo,
Textile Fibres. 2d Edition, Rewritten 8vo.
* Meyer's Determination of Radicles in Carbon Compounds. (Tingle.)
Third Edition 12mo.
Miller's Cyanide Process l2mo,
Manual of Assaying 12mo,
Minet's Production of Aluminum and its Industrial Use. ( Waldo. )...12mo,
* Mittelstaedt's Technical Calculations for Sugar Works. (Bourbakis.) 12mo,
Mixter's Elementary Text-book of Chemistry 12mo.
Morgan's Elements of Physical Chemistry 12mo,
* Physical Chemistry for Electrical Engineers 12mo,
* Moore's Experiments in Organic Chemistry 12mo,
* Outlines .of Organic Chemistry 12mo,
Morse's Calculations used in Cane-sugar Factories 16mo, mor.
* Muir's History of Chemical Theories and Laws 8vo,
Mulliken's General Method for the Identification of Pure Organic Compounds.
Vol. I. Compounds of Ckrbon with Hydrogen and Oxygen. Large 8vo,
Vol. II. Nitrogenous Compounds. (In Preparation.)
Vol. III. The Commercial Dyestuffs Large 8vo,
* Nelson's Analysis of Drugs and Medicines 12mo,
Oslwald's Conversations on Chemistry. Part One. (Ramsey.) 12mo,
Part Two. (Tumbull.) 12mo,
* Introduction to Chemistry. (Hall and Williams.) Large 12mo,
Owen and Standage's Dyeing and Cleaning of Textile Fabrics 12mo,
* Palmer's Practical Test Book of Chemistry 12mo,
* Pauli's Physical Chemistry in the Service of Medicine. (Fischer.). .12mo,
Penfield's Tables of Minerals, Including the Use of Minerals and Statistics
of Domestic Production 8vo,
Pictet's Alkaloids and their Chemical Constitution. (Biddle.) 8vo,
Poole's Calorific Power of Fuels 8vo,
Prescott and Winslow's Elements of Water Bacteriology, with Special Refer-
ence to Sanitary Water Analysis 12mo,
* Reisig's Guide to Piece-Dyeing 8vo,
Richards and Woodman's Air, Water, and Food from a Sanitary Stand-
point > 8vo.
Ricketts and Miller's Notes on Assaying 8vo,
Rideal's Disinfection and the Preservation of Food 8vo,
Riggs's Elementary Manual for the Chemical Laboratory 8vo,
Robine and Lenglen's Cyanide Industry. (Le Clerc.) 8vo,
Rudilinian's Incompatibilities in Prescriptions 8vo,
Whys in Pharmacy 12mo,
* Ruer's Elements of Metallography. (Mathewson.) 8vo,
Sabin's Industrial and Artistic Technology of Paint and Varnish 8vo,
Salkowski's Physiological and Pathological Chemistry. (Omdorff.) 8vo,
* Schimpf's Essentials of Volumetric Analysis Large 12mo,
Manual of Volumetric Analysis. (Fifth Edition, Rewritten) 8vo,
* Qualitative Chemical Analysis 8vo,
* Seamon's Manual for Assayers and Chemists Large 12mo
Smith's Lecture Notes on Chemistry for Dental Students 8vo,
Spencer's Handbook for Cane Sugar Manufacturers 16mo, mor.
Handbook for Chemists of Beet-sugar Houses 16mo, mor.
Stockbridge's Rocks and Soils 8vo,
Stone's Practical Testing of Gas and Gas Meters 8vo,
* Tillman's Descriptive General Chemistry 8vo,
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* Tillman's Elementary Lessons in Heat 8vo,
Treadwell's Quilitative Analysis. (Hall.) 8vo,
Quantitative Analysis. (Hall.) 8vo,
Tumeaure and Russell's Public Water-supplies .Svo,
Van Deventer's Physical Chemistry for Beginners. (Boltivood.) 12mo,
Vcnable's Methods and Devices for Bacterial Treatment of Sewage Svo,
Ward and Whipple's Freshwater Biology. (In Press.)
Ware's Beet-sugar Manufacture and Refining. Vol. I Svo,
Vol.11 Svo.
Washington's Manual of the Chemical Analysis of Rocks Svo,
* Weaver's Military Explosives Svo,
Wells's Laboratory Guide in Qualitative Chemical Analysis Svo,
Short Course in Inorganic Qualitative Chemical Analysis for Engineering
Students 12mo,
Text-book of Chemical Arithmetic 12mo,
Whipple's Microscopy of Drinking-water Svo,
Wilson's Chlorination Process l2rao.
Cyanide Processes 1 2nio,
Winton's Microscopy of Vegetable Foods Svo,
Zsigmondy's Colloids and the Ultramicroscope. (Alexander.).. Large 12mo,
CIVIL ENGINEERING.
BRIDGES AND ROOFS. HYDRAULICS. MATERIALS OP ENGINEER-
ING. RAILWAY ENGINEERING.
* American Civil Engineers' Pocket Book. (Mansfield Merriman, Editor-
in-chief.) 16m(>. mor.
Baker's Engineers' Surveying Instruments 12rao,
Bixby's Graphical Computing Table Paper 19i X24} inches.
Breed and Hosmer's Principles and Practice of Survey-ing. Vol. I. Elemen-
tary Surveying Svo,
Vol. II. Higher Surveying Svo,
* Burr's Ancient and Modern Engineering ana the Isthmian Canal Svo,
Comstock's Field Astronomy for Engineers Svo,
* Corthell's Allowable Pressure on Deep Foundations 12mo,
Crandall's Text-book on Geodesy and Least Squares Svo,
Davis's Elevation and Stadia Tables Svo,
Elliott's Engineering for Land Drainage 12mo,
* Fiebeger's Treatise on Civil Engineering Svo,
Flemer's Photo topographic Methods and Instruments Svo,
Folwell's Sewerage. (Designing and Maintenance.) Svo,
Freitag's Architectural Engineering Svo,
French and Ives's Stereotomy Svo,
Gilbert, Wightman, and Saunders's Subways and Tunnels of New York.
(In Press.)
* Hauch and Rice's Tables of Quantities for Preliminary Estimates. . . l2mo,
Hayford's Text-book of Geodetic Astronomy Svo,
Hering's Ready Reference Tables (Conversion Factors.) 16mo, mor.
Hosmer's Azimuth 16mo, mor.
* Text-book on Practical Astronomy Svo,
Howe's Retaining Walls for Eartk 12mo,
* Ives's Adjustments of the Engineer's Transit and Level I6mo, bds.
Ives and Hilts's Problems in Surveying, Railroad Surveying and Geod-
esy 16mo, mor.
* Johnson (J.B.) and Smith's Theory and Practice of Surveying. Large I2mo,
Johnson's (L. J.) Statics by Algebraic and Graphic Methods Svo,
* Kinnicutt, Winslow and Pratt's Sewage Disposal •. . . .Svo,
* Mahan's Descriptive Geometry Svo,
Merriman's Elements of Precise Surveying and Geodesy Svo,
Merriman and Brooks's Handbook for Surveyors ^ . . . . 16mo, mor.
Nugent's Plane Surveying Svo,
Ogden's Sewer Construction Svo,
Sewer Design 12mo.
Parsons's Disposal of Municipal Refuse Svo,
Patton's Treatise on Civil Engineering Svo, half leather.
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Reed's Topographical Drawing and Sketching 4to, $5 00
Riemer's Shaft-sinking under Difficult Conditions. (Coming and PeeIe.).8vo. 3 00
Siebert and Biggin's Modem Stone-cutting and Masonry 8vo, 1 50
Smith's Manual of Topographical Drawing. (McMillan.) 8vo, 2 50
Soper's Air and Ventilation of Subways 12mo, 2 50
* Tracy's Exercises in Surveying 12mo, mor. 1 00
Tracy's Plane Surveying 16mo, mor. 3 00
Venable's Garbage Crematories in America 8vo, 2 00
Methods and Devices for Bacterial Treatment of Sewage 8vo, 3 00
Wait's Engineering and Architectural Jurisprudence 8vo, 6 00
Sheep. 6 50
Law of Contracts 8vo, 3 00
\aw of Operations Preliminary to Construction in Engineering and
Architecture 8vo, 5 00
Sheep, 5 50
Warren's Stereotomy — Problems in Stone-cutting 8vo, 2 50
* Waterbury's Vest-Pocket Hand-book of Mathematics for Engineers.
2iX5| inches, mor. 1 00
* Enlarged Edition, Including Tables nor. 1 50
Webb's Problems in the Use and Adjustment of Engineering Instruments.
I6mo, mor. 1 25
Wilson's Topographic Surveying 8vo, 3 50
BRIDGES AND ROOFS.
Boiler's Practical Treatise on the Construction of Iron Highway Bridges.. 8vo
* Thames River Bridge Oblong paper
Burr and Falk's Design and Construction of Metallic Bridges 8vo
Influence Lines for Bridge and Roof Computations 8vo
Du Bois's Mechanics of Engineering. Vol. II Sma 4 to
Foster's Treatise on Wooden Trestle Bridges 4to
Fowler's Ordinary Foundations 8vo
Greene's Arches in Wood. Iron, and Stone 8vo
Bridge Trusses 8vo
Roof Trusses 8vo
Grimm's Secondary Stresses in Bridge Trusses 8vo
Heller's Stresses in Structures and the Accompanying Deformations.. . .8vo
Howe's Design of Simple Roof- trusses in Wood and Steel 8vo
Symmetrical Masonry Arches 8vo
Treatise on Arches 8vo
* Hudson's Deflections and Statically Indeterminate Stresses Small 4to
* Plate Girder Design 8vo
* Jacoby's Structural Details, or Elements of Design in Heavy Framing; 8vo
Johnson. Bryan and Tumeaure's Theory and Practice in the Designing of
Modem Framed Structures Small 4to
* Johnson, Bryan and Tumeaure's Theory and Practice in the Designing of
Modem Framed Structures. New Edition. Part 1 8vo
* Part II. New Edition 8vo
Merriman and Jacoby's Text-book on Roofs and Bridges:
Part I.
Part II.
Part III.
Part IV.
Sondericker's
Stresses in Simple Trusses 8vo
Graphic Statics 8vo
Bridge Design 8 vo
Higher Structures 8 vo
Graphic Statics, with Applications to Trusses, Beams, and
Arches 8vo
Waddell's De Pontibus. Pocket-book for Bridge Engineers 16mo, mor
* Specifications for Steel Bridges 12mo
Waddell and Harrington's Bridge Engineering. (In Preparation.)
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HYDRAULICS.
Barnes's Ice Formation 8vo, 3 00
Bazin's Experiments upon the Contraction of the Liquid Vein Issuing from
an Orifice. (Trautwine.) 8vo, 2 00
Bovey's Treatise on Hydraulics 8vo, 5 00
7
Church's Diagrams of Mean Velocity of Water in Open Channels.
Oblong 4to, paper, $1 50
Hydraulic Motors 8vo, 2 00
Mechanics of Fluids (Being Part IV of Mechanics of Engineering) . .8vo, 3 00
Coffin's Graphical Solution of Hydraulic Problems 16mo, mor. 2 60
Flather's Dynamometers, and the Measurement of Power 12mo. 3 00
Folwell's Water-supply Engineering 8vo. 4 00
Frizell's Water-power 8vo, 5 00
Fuertes's Water and Public Health 12mo, 1 50
Water-filtration Works 12mo, 2 50
Ganguillet and Kutter's General Formula for the Uniform Flow of Water in
Rivers and Other Channels. (Hering and Trautwine.) 8vo, 4 00
Hazen's Clean Water and How to Get It Large 12mo, ' 1 50
Filtration of Public Water-supplies 8vo, 3 00
Hazelhtirst's Towers and Tanks for Water- works 8vo, 2 50
Herschel's 115 Experiments on the Carrying Capacity of Large, Riveted, Metal
Conduits 8vo, 2 00
Hoyt and Grover's River Discharge 8vo, 2 00
Hubbard and Kiersted's Water-works Management and Maintenance.
8vo, 4 00
* Lyndon's Development and Electrical Distribution of Water Power.
8vo, 3 00
Mason's Water-supply. (Considered Principally from a Sanitary Stand-
point.) 8vo, 4 00
Merriman's Treatise on Hydraulics 8vo, 5 00
* Molitor's Hydraulics of Rivers, Weirs and Sluices 8vo, 2 00
* Morrison and Brodie's High Masonry Dam Design 8vo, 1 50
* Richards's Laboratory Notes on Industrial Water Analysis 8vo, 50
Schuyler's Reservoirs for Irrigation, Water-power, and Domestic Water-
supply. Second Edition, Revised and Enlarged Large 8vo, 6 00
* Thomas and Watt's Improvement of Rivers •. 4to, 6 00
Turneaure and Russell's Public Water-supplies .Svo, 5 00
* Wegmann's Design and Construction of Dams. 6th Ed., enlarged 4to, 6 00
Water-Supply of the City of New York from 1658 to 1895 : .4to. 10 00
Whipple's Value of Pure Water Large 12mo, 1 00
Williams and Hazen's Hydraulic Tables 8vo, 1 50
Wilson's Irrigation Engineering 8vo, 4 00
Wood's Turbines 8vo. 2 50
MATERIALS OF ENGINEERING.
Baker's Roads and Pavements 8vo, 5 00
Treatise on Masonry Construction 8vo, 5 00
Black's United States Public Works Oblong 4to, 5 00
Blanchard and Drowne's Highway Engineering. (In Press.)
Bleininger's Manufacture of Hydraulic Cement. (In Preparation.)
Bottler's Varnish Making. (Sabin.) (In Press.)
Burr's Elasticity and Resistance of the Materials of Engineering 8vo, 7 50
Byrne's Highway Construction 8vo, 5 00
Inspection of the J?Iaterials and Workmanship Employed in Construction.
16mo, 3 00
Church's Mechanics of Engineering 8vo, 6 00
Mechanics of Solids (Being Parts I, II, III of Mechanics of Engineer-
ing 8vo. 4 50
Du Bois's Mechanics of Engineering.
Vol. I. Kinematics, Statics, Kinetics Small 4to, 7 50
Vol. II. The Stresses in Framed Structures, Strength of Materials and
Theory of Flexures Small 4to, 10 00
Eckel's Building Stones and Clays. (In Press.)
* Cements, Limes, and Plasters 8vo, 6 00
Fowler's Ordinary Foundations 8vo, 3 50
* Greene's Structural Mechanics 8vo. 2 50
HoUey's Analysis of Paint and Varnish Products. (In Press.)
* Lead and Zinc Pigments Large 12mo./ 3 00
* Hubbard's Dust Preventives and Road Binders 8vOp 3 00
8
Johnson's (C. M.) Rapid Methods for the Chemical Analysis of Special Steels
Steel-making Alloys and Graphite Large 12mo
Johnson's (J. B.) Materials of Construction Large 8vo
Keep's Cast Iron 8vo
Lanza's Applied Mechanics 8vo
Lowe's Paints for Steel Structures 12mo
Maire's Modem Pigments and their Vehicles 12mo
Maurer's Technical Mechanics 8vo
Merrill's Stones for Building and Decoration 8vo
Merriman's Mechanics of Materials 8vo
* Strength of Materials 12mo
Metcalf 's Steel. A Manual for Steel-users 12mo
Morrison's Highway Engineering , 8vo
* Murdock's Strength of Materials 12mo
Patton's Practical Treatise on Foimdations 8vo
Rice's Concrete Block Manufacture 8vo
Richardson's Modem Asphalt Pavement 8vo
Richey's Building Foreman's Pocket Book and Ready Reference. 16mo, mor
* Cement Workers' and Plasterers' Edition (Building Mechanics' Ready
Reference Series) 16mo, mor;
Handbook for Superintendents of Construction 16mo, mor.
* Stone and Brick Masons' Edition (Building Mechanics' Ready
Reference Series) 16mo, mor.
* Ries's Clays : Their Occurrence, Properties, and Uses 8vo,
* Ries and Leighton's History of the Clay-working Industry of the United
States 8vo.
Sabin's Industrial and Artistic Technology of Paint and Varnish 8vo,
* Smith's Strength of Material 12mo,
Snow's Principal Species of Wood 8vo,
Spalding's Hydraulic Cement 12mo,
Text-book on Roads and Pavements 12mo,
* Taylor and Thompson's Extracts on Reinforced Concrete Design 8vo,
Treatise on Concrete, Plain and Reinforced 8vo,
Thurston's Materials of Engineering. In Three Parts 8vo,
Part I. Non-metallic Materials of Engineering and Metallurgy. . . .8vo,
Part II. Iron and Steel 8vo,
Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their
Constituents 8vo,
Tillson's Street Pavements and Paving Materials 8vo,
Tumeaure and Maurer's Principles of Reinforced Concrete Construction.
Second Edition, Revised and Enlarged 8vo,
Waterbury's Cement Laboratory Manual 12mo,
Laboratory Manual for Testing Materials of Construction. (In Press.)
Wood's (De V.) Treatise on the Resistance of Materials, and an Appendix on
the Preservation of Timber 8vo,
Wood's (M. P.) Rustless Coatings: Corrosion and Electrolysis of Iron and
Steel 8 vo,
$3 00
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2 00
4 00
RAILWAY ENGINEERING.
Andrews's Handbook for Street Railway Engineer.*; 3X5 inches, mor 1 25
Berg's Buildings and Structures of American Railroads 4to, 5 00
Brooks's Handbook of Street Railroad Location I6mo, mor. 1 50
* Burt's Railway Station Service 12mo, 2 00
Butts's Civil Engineer's Field-book 16mo, mor. 2 50
Crandall's Railway and Other Earthwork Tables 8vo, 1 50
Crandall and Barnes's Railroad Surveying I6mo, mor. 2 00
* Crockett's Methods for Earthwork Computations 8vo, 1 50
Dredge's History of the Pennsylvania Railroad. (1879) Paper, 5 00
Fisher's Table of Cubic Yards Cardboard, 25
Godwin's Railroad Engineers' Field-book and Explorers' Guide. . 16mo, mor. 2 50
Hudson's Tables for Calculating the Cubic Contents of Excavations and Em-
bankments 8vo, 1 00
Ives and Hilts's Problems in Surveying, Railroad Surveying and Geodesy
Iftmo, mor. 1 50
Molitor and Beard's Manual for Resident Engineers 16mo, 1 00
9
Nagle's Field Manual for Railroad Engineers 16mo, mor, $3 OO
* Orrock's Railroad Structures and Estimates 8vo, 3 OO
Philbrick's Field Manual for Engineers 16mo, mor. 3 OO
Raymond's Railroad Field Geometry .' 16mo, mor. 2 OO
Elements of Railroad Engineering .8vo, 3 50
Railroad Engineer's Field Book. (In Preparation.)
Roberts' Track Formulae and Tables 16mo. mor. 3 OO
Searles's Field Engineering 16mo, mor. 3 00
Railroad Spiral 16mo, mor. 1 50
Taylor's Prismoidal Formulae and Earthwork 8vo, 1 50
Webb's Economics of Railroad Construction Large 12mo, 2 50
Railroad Construction 16mo, mor. 5 00
Wellington's Economic Theory of the Location of Railways Large 12mo, 5 00
Wilson's Elements of Railroad-Track and Construction 12mo, 2 00
DRAWING
Barr and Wood's Kinematics of Machinery 8vo, 2 50-
* Eartlett's Mechanical Drawing 8vo, ? OO
* " •• •* Abridged Ed 8vo, 1 50
* Bartlett and Johnson's Engineering Descriptive Geometry 8vo, 1 60
Blessing and Darling's Descriptive Geometry. (In Press.)
Elements of Drawing. (In Press.)
Coolidge's Manual of Drawing 8vo, paper, 1 00
Coolidge and Freeman's Elements of General Drafting for Mechanical Engi-
neers Oblong 4to, 2 50
Durley's Kinematics of Machines 8vo, 4 00*
Emch's Introduction to Projective Geometry and its Application .8vo, 2 50
Hill's Text-book on Shades and Shadows, and Perspective 8vo, 2 OO
Jamison's Advanced Mechanical Drawing 8vo, 2 OO
Elements of Mechanical Drawing 8vo, 2 50
Jones's Machine Design:
Part I. Kinematics of Machinery 8vo, 1 50
Part II. Form, Strength, and Proportions of Parts 8vo, 3 00>
* Kimball and Barr's Machine Design 8vo, 3 OO
MacCord's Elements of Descriptive Geometry 8vo, 3 OO
Kinematics; or. Practical Mechanism 8vo, 5 OO
Mechanical Drawing 4to, 4 00
Velocity Diagrams 8vo, 1 50'
McLeod's Descriptive Geometry Large 12mo, 1 50
* Mahan's Descriptive Geometry and Stone-cutting 8vo, 1 50
Industrial Drawing. (Thompson.) ^. . . .'. 8vo, 3 50
Moyer's Descriptive Geometry 8vo, 2 OO
Reed's Topographical Drawing and Sketching 4to, 5 00
* Raid's Mechanical Drawing. (Elementary and Advanced.) 8vo, 2 00
Text-book of Mechanical Drawing and Elementary Machine Design.. 8vo, 3 00-
Robinson's Principles of Mechanism , 8vo, 3 00
Schwamb and Merrill's Elements of Mechanism 8vo, 3 00
Smith (A. W.) and Marx's Machine Design 8vo, 3 00-
Smith's (R. S.) Manual of Topographical Drawing. (McMillan.) 8vo, 2 50
* Titsworth's Elements of Mechanical Drawing Oblong 8vo, 1 25
Tracy and North's Descriptive Geometry. (In Press.)
Warren's Elements of Descriptive Geometry, Shadows, and Perspective. . 8vo, 3 50
Elements of Machine Construction and Drawing 8vo, 7 50-
Elements of Plane and Solid Free-hand Geometrical Drawing. . . . I2mo, 1 00"
General Problems of Shades and Shadows 8vo, 3 00-
Manual of Elementary Problems in the Linear Perspective of Forms and
Shadow 12mo, 1 00
Manual of Elementary Projection Drawing 12mo, 1 50
Plane Problems in Elementary Geometry 12mo, 1 25«
Weisbach's Kinematics and Power of Transmission. (Hermann and
Klein.) 8vo, 6 OO
Wilson's (H. M.) Topographic Surveying 8vo, 3 50
* Wilson's (V. T.) Descriptive Geometry 8vo, 1 50
Free-hand Lettering 8vo, 1 OO
Free-hand Perspective 8vo, 2 50
Woolf's Elementary Course in Descriptive Geometry Large 8vo, 3 OO
10
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25;
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ELECTRICITY AND PHYSICS.
* Abegg's Theory of Electrolytic Dissociation, (von Ende."> 12mo,
Andrews's Hand-book for Street Railway Engineers 3X5 inches mor.
i^nthony and Ball's Lecture-notes on the Theory of Electrical Measure-
ments 12mo,
Anthony and Brackett's Text-book of Physics. (Magie.). .. .Large 12mo,
Benjamin's History of Electricity 8vo,
Betts's Lead Refining and Electrolysis 8vo,
Burgess and Le Chatelier's Measurement of High Temperatures. Third
Edition. (In Press.)
Classen's Quantitative Chemical Analysis by Electrolysis. (Boltwood.).8vo,
* Collins's Manual of Wireless Telegraphy and Telephony 12mo,
Crehore and Squier's Polarizing Photo-chronograph Svo,
* Danneel's Electrochemistry. (Merriam.) 12mo,
Dawson's "Engineering" and Electric Traction Pocket-book. . . . 16mo. mor.
Dolezalek's Theory of the Lead Accumulator (Storage Battery), (von Ende.)
12mo,
Duhem's Thermodynamics and Chemistry. (Burgess.) Svo,
Flather's Dynamometers, and the Measurement of Power 12mo,
* Getman's Introduction to Physical Science 12mo,
Gilbert's De Magnete. (Mottelay ) Svo,
* Hanchett's Alternating Currents 12mo,
Hering's Ready Reference Tables (Conversion Factors) 16mo, mor.
* Hobart and Ellis's High-speed Dynamo Electric Machinery Svo,
Holman's Precision of Measurements Svo,
Telescope- Mirror-scale Method, Adjustments, and Tests Large Svo,
* Hutchinson's High-Efficiency Electrical lUuminants and Illumination.
' Large 12mo, 2 50'
Jones's Electric Ignition. (In Press.)
Karapetoff's Experimental Electrical Engineering:
* Vol. I Svo.
* Vol. II , Svo,
Kinzbrunner's Testing of Continuous-current Machines Svo,
Landauer's Spectrum Analysis. (Tingle.) Svo,
Lob's Electrochemistry of Organic Compounds. (Lorenz.) Svo,
* Lyndon's Development and Electrical Distribution of Water Power. .Svo,
* Lyons's Treatise On Electromagnetic Phenomena. Vols. I. and II. Svo, each,
* Michie's Elements of Wave Motion Relating to Sound and Light Svo,
* Morgan's Physical Chemistry for Electrical Engineers 12mo,
* Norris's Introduction to the Study of Electrical Engineerisg Svo.
Norris and Dennison's Course of Problems on the Electrical Characteristics of
Circuits and Machines. (In Press.)
* Parshall and Hobart's Electric Machine Design 4to, half mor, 12 50
Reagan's Locomotives: Simple, Compound, and Electric. New Edition.
Large 12mo, 3 50
* Rosenberg's Electrical Engineering. (Haldane Gee — Kinzbrunner.). .Svo, 2 00-
Ryan, Norris, and Hoxie's Electrical Machinery. Vol. I Svo, 2 50-
Schapper's Laboratory Guide for Students in Physical Chemistry l2mo, 1 00-
* Tillman's Elementary Lessons in Heat Svo. 1 50-
* Timbie's Elements of Electricity Large 12mo, 2 00
Tory and Pitcher's Manual of Laboratory Physics Large 12mo, 2 00-
Ulke's Modem Electrolytic Copper Refining Svo, 3 00
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LAW.
* Brennan's Hand-book of Useful Legal Information for Business Men.
16mo, mor. 5 00"
* Davis's Elements of Law Svo, 2 50-
* Treatise on the Military Law of United States Svo, 7 00
* Dudley's Military Law and the Procedure of Courts-martial. . Large 12mo, 2 50
Manual for Courts-martial 16mo, mor. 1 50
Wait's Engineering and Architectural Jurisprudence -.Svo, 6 00
Sheep, 6 50
Writ's Law of Contracts Svo, 3 OO
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Wait's Law of Operations Preliminary to Construction in Engineering and
Architecture .* 8vo, $5 00
Sheep, 5 50
MATHEMATICS.
«
Baker's Elliptic Functions 8vo, 1 60
Briggs's Elements of Plane Analytic Geometry. (Bdcher.) 12mo, 1 00
* Buchanan's Plane and Spherical Trigonometry '. 8vo, 1 00
Byerly's Harmonic Functions 8vo, 1 00
Chandler's Elements of the Infinitesimal Calculus 12mo, 2 00
* Coffin's Vector Analysis 12mo, 2 50
■Compton's Manual of Logarithmic Computations 12mo, 1 50
* Dickson's College Algebra Large 12mo, 1 50
* Introduction to the Theory of Algebraic Equations Large 12mo. 1 25
Emch's Introduction to Projective Geometry and its Application 8vo, 2 50
Fiske's Functions of a Complex Variable 8vo, 1 00
Halsted's Elementary Synthetic Geometry 8vo, 1 50
Elements of Geometry 8vo, 1 75
* Rational Geometry 12mo, 1 50
Synthetic Projective Geometry 8vo, 1 00
* Hancock's Lectures on the Theory of Elliptic Functions 8vo, 5 00
Hyde's Grassmann's Space Analysis 8vo, 1 00
* Johnson's (J. B.) Three-place Logarithmic Tables: Vest-pocket size, paper, 15
* 100 copies, 5 00
* Mounted on heavy cardboard, 8 X 10 inches, 25
* 10 copies, 2 00
Johnson's (W. W.) Abridged Editions of Differential and Integral Calculus.
Large 12mo, 1 vol. 2 50
Curve Tracing in Cartesian Co-ordinates 12mo, 1 00
Differential Equations 8vo, 1 00
Elementary Treatise on Differential Calculus Large 12mo, 1 60
Elementary Treatise on the Integral Calculus Large 12mo, 1 50
* Theoretical Mechanics 12mo, 3 00
Theory of Errors and the Method of Least Squares 12mo, 1 50
Treatise on Differential Calculus Large 12mo, 3 00
Treatise on the Integral Calculus Large 12mo, 3 00
Treatise on Ordinary and Partial Differential Equations. . .Large 12mo, 3 50
* Karapetoff 's Engineering Applications of Higher Mathematics. Large 12mo, 75
Koch's Practical Mathematics, (In Press.)
Laplace's Philosophical Essay on Probabilities. (Truscott and Emory.) .12mo, 2 00
* Le Messurier's Key to Professor W. W. Johnson's Differential Equations.
Small 8vo, 1 75
* Ludlow's Logarithmic and Trigonometric Tables 8vo, 1 00
J" Ludlow and Bass's Elements of Trigonometry and Logarithmic and Other
Tables 8vo, 3 00
* Trigonometry and Tables published separately Each, 2 00
Macfarlane's Vector Analysis and Quaternions 8vo, 1 00
McMahon's Hyperbolic Functions 8vo, 1 00
Manning's Irrational Numbers and their Representation by Sequences and
Series 12mo. 1 25
Mathematical Monographs. Edited by Mansfield Merriman and Robert
S. Woodward Octavo, each 1 00
No. 1. History of Modern Mathematics, by David Eugene Smith.
No. 2, Synthetic Projective Geometry, by George Bruce Halsted.
No. 3. Determinants, by Laenas Gifford Weld. No. 4. Hyper-
bolic Functions, by James McMahon. No. 5. Harmonic Func-
tions, by William E. Byerly. No. 6. Grassmann's Space Analysis,
by Edward W. Hyde, No. 7. Probability and Theory of Errors,
by Robert S. Woodward. No. 8. Vector Analysis and Quaternions,
by Alexander Macfarlane. No. 9. Differential Equations, by
William Woolsey Johnson. No. 10. The Solution of Equations,
by Mansfield Merriman. No. 11. Functions of a Complex Variable,
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Maurer's Technical Mechanics 8vo, 4 00
JMerriman's Method of Least Squares 8vo, 2 00
Solution of Equations 8vo, 1 00
12
* Moritz's Elements of Plane Trigonometry 8vo, $2 00
Rice and Johnson's Differential and Integral Calculus. 2 vols, in one.
Large 12mo, 1 50
Elementary Treatise on the Differential Calculus Large 12mo, 3 GO
Smith's History of Modem Mathematics 8vo, 1 GO
* Veblen and Lennes's Introduction to the Real Infinitesimal Analysis of One
Variable 8vo, 2 GO
* Waterbury's Vest Pocket Hand-book of Mathematics for Engineers.
2iX5f inches, mor. 1 00
* Enlarged Edition, Including Tables mor. 1 60
Weld's Determinants 8vo, 1 00
Wood's Elements of Co-ordinate Geometry 8vo, 2 00
Woodward's Probability and Theorj' of Errors 8vo, 1 00
MECHANICAL ENGINEERING.
MATERIALS OF ENGINEERING, STEAM-ENGINES AND BOILERS.
Bacon's Forge Practice 12mo,
Baldwin's Steam Heating for Buildings 12mo,
Barr and Wood's Kinematics of Machinery 8vo,
* Bartlett's Mechanical Drawing 8vo,
* " •• " Abridged Ed 8vo,
* Bartlett and Johnson's Engineering Descriptive Geometry 8vo,
* Burr's Ancient and Modern Engineering and the Isthmian Canal 8vo,
Carpenter's Heating and Ventilating Buildings 8vo,
* Carpenter and Diederichs's Experimental Engineering 8vo,
* Clerk's The Gas. Petrol and Oil Engine 8vo.
Compton's First Lessons in Metal Working 12mo,
Compton and De Groodt's Speed Lathe 12mo,
■Coolidge's Manual of Drawing 8vo, paper,
Coolidge and Freeman's Elements of General Drafting for Mechanical En-
gineers Oblong 4to,
Cromwell's Treatise on Belts and Pulleys 12mo,
Treatise on Toothed Gearing l2mo,
Dingey's Machinery Pattern Making 12mo,
Durley's Kinematics of Machines 8vo,
Flanders's Gear-cutting Machinery Large I2mo,
Flather's Dynamometers and the Measurement of Power 12mo,
Rope Driving 12mo,
Gill's Gas and Fuel Analysis for Engineers 12mo,
Goss's Locomotive Sparks 8vo,
* Greene's Pumping Machinery 8vo.
Hering's Ready Reference Tables (Conversion Factors) 16mo. mor.
* Hobart and Ellis's High Speed Dynamo Electric Machinery Svo,
Hutton's Gas Engine Svo,
Jamison's Advanced Mechanical Drawing Svo,
Elements of Mechanical Drawing Svo.
Jones's Gas Engine Svo.
Machine Design:
Part I. Kinematics of Machinery Svo,
Part II. Form. Strength, and Proportions of Parts Svo,
* Kaup's Machine Shop Practice Large 12mo,
* Kent's Mechanical Engineer's Pocket-Book 16mo, mcr.
Kerr's Power and Power Transmission Svo,
* Kimball and Barr's Machine Design Svo.
* King's Elements of the Mechanics of Materials and of Power of Trans-
mission Svo,
* Lanza's Dynamics of Machinery Svo,
Leonard's Machine Shop Tools and Methods Svo,
* Levin's Gas Engine Svo,
* Lorenz's Modem Refrigerating Machinery. (Pope, Haven, and Dean).. Svo,
MacCord's Kinematics; or. Practical Mechanism Svo,
Mechanical Drawing 4to,
Velocity Diagrams ...» Svo,
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MacFarland's Standard Reduction Factors for Gases 8vo,
Mahan's Industrial Drawing. (Thompson.) 8vo,
Mehrtens's Gas Engine Theory and Design Large 12mo,
Miller, Berry, and Riley's Problems in Thermodynamics and Heat Engineer-
inj 8vo, paper,
Oberg's Handbook of Small Tools Large 12mo,
* Parshall and Hobart's Electric Machine Design. Small 4to. half leather,
* Peele's Compressed Air Plant. Second Edition, Revised and Enlarged . 8vo,
Perkins's General Thermodynamics. (In Press.)
Poole's Calorific Power of Fuels 8vo,
* Porter's Engineering Reminiscences. 1855 to 1882 8vo,
Randall's Treatise on Heat. (In Press.)
* Reid's Mechanical Drawing. (Elementary and Advanced.) 8vo,
Text-book of Mechanical Drawing and Elementary Machine Design.8vo,
Richards's Compressed Air 12mo,
Rdbinson's Principles of Mechanism 8vo,
Schwamb and Merrill's Elements of Mechanism 8vo,
Smith (A. W.) and Marx's Machine Design 8vo,
Smith's (O.) Press-working of Metals 8vo,
Sorel's Carbureting and Combustion in Alcohol Engines. (Woodward and
Preston.) Large 12mo,
Stone's Practical Testing of Gas and Gas Meters 8vo,
Thurston's Animal as a Machine and Prime Motor, and the Laws of Energetics.
12mo,
Treatise on Friction and Lost Work in Machinery and Mill Work. . .8vo,
* Tillson's Complete Automobile Instructor 16mo,
* Titsworth's Elements of Mechanical Drawing Oblong 8vo,
Warren's Elements of Machine Construction and Drawing 8vo,
* Waterbury's Vest Pocket Hand-book of Mathematics for Engineers.
2jX5f inches, mor.
* Enlarged Edition, Including Tables mor.
Weisbach's Kinematics and the Power of Transmission. (Herrmann —
Klein.) 8vo,
Machinery of Transmission and Governors. (Hermann — Klein.). .8vo,
Wood's Turbines 8vo,
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2 50
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MATERIALS OF ENGINEERING.
Burr's Elasticity and Resistance of the Materials of Engineering 8vo
Church's Mechanics of Engineering 8vo
Mechanics of Solids (Being Parts I, IT, III of Mechanics of Engineering)
8vo
* Greene's Structural Mechanics 8vo
Holley's Analysis of Paint and Varni.sh Products. (In Press.)
* Lead and Zinc Pigments Large 12mo
Johnson's (C. M.) Rapid Methods for the Chemical Analysis of Special
Steels, Steel-Making Alloys and Graphite Large 12mo
Johnson's (J. B.) Materials of Construction 8vo
Keep's Cast Iron 8vo
* King's Elements of the Mechanics of Materials and of Power of Trans-
mission 8vo
Lanza's Applied Mechanics 8vo
Lowe's Paints for Steel Structures 12mo
Maire's Modem Pigments and their Vehicles 12mo
Maurer's Technical Mechanics 8vo
Merriman's Mechanics of Materials 8vo
* Strength of Materials 12mo
Metcalf's Steel. A Manual for Steel-users 12mo
* Murdock's Strength of Materials 12mo
Sabin's Industrial and Artistic Technology of Paint and Varnish 8vo
Smith's (A. W.) Materials of Machines 12mo
* Smith's (H. E.) Strength of Material 12mo
Thurston's Materials of Engineering 3 vols., 8vo
Part I. Non-metallic Materials of Engineering, 8vo
Part II. Iron and Steel 8vo
Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their
Constituents 8vo.
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"Waterbury's Laboratory Manual for Testing Materials of Construction.
(In Press.)
Wood's (De V.) Elements of Analytical Mechanics 8vo, $3 00
Treatise on the Resistance of Materials and an Appendix on tlie
Preservation of Timber 8vo, 2 00
Wood's (M. P.) Rustless Coatings: Corrosion and Electrolysis of Iron and
Steel 8vo, 4 00
STEAM-ENGINES AND BOILERS.
Berry's Temperature-entropy Diagram. Third Edition Revised and En
largcd 12mo
■Camot's Reflections on the Motive Power of Heat. (Thurston.) 12mo
Chase's Art of Pattern Making 12mo
Creigh ton's Steam-engine and other Heat Motors 8vo
Dawson's "Engineering" and Electiic Traction Pocket-book. .. . Ibmo, mor
* Gebhardt's Steam Power Plant Engineering 8vo
■Goss's Locomotive Performance 8vo
Hemenway's Indicator Practice and Steam-engine Economy 12mo
Hirshfeld and Barnard's Heat Power Engineering. (In Press.)
Hutton's Heat and Heat-engines 8vo
Mechanical Engineering of Power Plants 8vo
Kent's Steam Boiler Economy 8vo
Kneass's Practice and Theory of the Injector 8vo
MacCord's Slide-valves 8vo
Meyer's Modem Locomotive Construction 4to
Miller, Berry, and Riley's Problems in Thermodynamics 8vo, paper
Moyer's Steam Turbine 8vo
Peabody's Manual of the Steam-engine Indicator 12mo
Tables of the Properties of Steam and Other Vapors and Temperature
Entropy Table 8vo
Thermodynamics of the Steam-engine and Other Heat-engines. . . .8vo
* Thermodynamics of the Steam Turbine 8vo
Valve-gears for Steam-engines 8vo
Peabody and Miller's Steam-boilers 8vo
Pupin's ThermodjTiamics of Reversible Cycles in Gases and Saturated Vapors
(Osterberg.) 12mo
Reagan's Locomotives: Simple, Compound, and Electric. New Edition.
Large 12mo
Sinclair's Locomotive Engine Running and Management 12mo
Smart's Handbook of Engineering Laboratory Practice 12mo
Snow's Steam-boiler Practice 8vo
Spangler's Notes on Thermodynamics 12mo
Valve-gears 8vo
Spangler, Greene, and Marshall's Elements of Steam-engineering 8vo
Thomas's Steam-turbines 8vo
Thurston's Handbook of Engine and Boiler Trials, and the Use of the Indi-
cator and the Prony Brake 8vo
Handy Tables 8vo
Manual of Steam-boilers, their Designs, Construction, and Operation 8vo
Manual of the Steam-engine " 2 vols., 8vo
Part I. History. Structure, and Theory 8vo
Part II. Design, Construction, and Operation 8vo
Wehrenfennig's Analysis and Softening of Boiler Feed-water. (Patterson )
8vo
Weisbach's Heat, Steam, and Steam-engines. (Du Bois.) 8vo
Whithams Steam-engine Design 8vo
Wood's Thermodynamics, Heat Motors, and Refrigerating Machines. . .8vo
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MECHANICS PURE AND APPLIED.
Church's Mechanics of Engineering 8vo, 6 00
Mechanics of Fluids (Being Part IV of Mechanics of Engineering). .8vo, 3 00
* Mechanics of Internal Works 8vo, 1 50
Mechanics of Solids (Being Parts I, II, III of Mechanics of Engineering).
8vo, 4 50
Notes and Examples in Mechanics 8vo, 2 00
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Dana's Text-book of Elementary Mechanics for Colleges and Schools .12mo, f 1 50
Du Bois's Elementary Principles of Mechanics:
Vol. I. Kinematics 8vo,
Vol. II. Statics 8vo.
Mechanics of Engineering. Vol. I Small 4to,
Vcl. II Small 4to,
* Greene's Structural Mechanics 8vo,
* Hartmann's Elementary Mechanics for Engineering Students 12mo,
James's Kinematics of a Point and the Rational Mechanics of a Particle.
Large 12mo.
* Johnson's (W. W.) Theoretical Mechanics 12mo,
* King's Elements of the Mechanics of Materials and of Power of Trans-
mission Svo,
Lanza's Applied Mechanics Svo,
* Martin's Text Book on Mechanics, Vol. I, Statics 12mo,
* Vol. II. Kinematics and Kinetics 12mo,
* Vol. III. Mechanics of Materials 12mo,
Maurer's Technical Mechanics Svo.
* Merriman's Elements of Mechanics 12mo,
Mechanics of Materials - Svo,
* Michie's Elements of Analytical Mechanics Svo,
Robinson's Principles of Mechanism Svo,
Sanborn's Mechanics Problems Large 12mo,
Schwamb and Merrill's Elements of Mechanism Svo,
Wood's Elements of Analytical Mechanics Svo,
Principles of Elementary Mechanics 12mo,
MEDICAL.
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Defren.) Svo, 5 OO
von Behring's Suppression of Tuberculosis. (Bolduan.) 12mo, 1 OO
* Bolduan's Immune Sera 12mo, 1 50
Bordet's Studies in Immunity. (Gay.) Svo, 6 00
* Chapin's The Sources and Modes of Infection Large 12mo, 3 OO
Davenport's Statistical Methods with Special Reference to Biological Varia-
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Ehrlich's Collected Studies on Immunity. (Bolduan.) Svo, 6 00
* Fischer's Nephritis Large 12mo, 2 50
* Oedema Svo, 2 OO
* Physiology of Alimentation Large 12mo, 2 00
* de Fursac's Manual of Psychiatry. (Rosanoff and Collins.) . . . Large 12mo, 2 50
* Hammarsten's Text- book on Physiological Chemistry. (Mandel.).. . .Svo, 4 00
Jackson's Directions for Laboratory Work in Physiological Chemistry . .Svo. 1 2S
Lassar-Cohn's Praxis of Urinary Analysis. (Lorenz.) 12mo, 1 OO
Mandel's Hand-book for the Bio-Chemical Laboratory 12mo. 1 50
* Nelson's Analysis of Drugs and Medicines l2mo, 3 OO
* Pauli's Physical Chemistry in the Service of Medicine. (Fischer.) ..12mo, 1 2S
* Pozzi-Escot's Toxins and Venoms and their Antibodies. (Cohn.). . 12mo, 1 OO
Rostoski's Serum Diagnosis. (Bolduan.) 12mo, 1 00
Ruddiman's Incompatibilities in Prescriptions Svo, 2 00
Whys in Pharmacy 12mo, 1 OO
Salkowski's Physiological and Pathological Chemistry. (Orndorff.) .. ..Svo, 2 50
* Satterlee's Outlines of Human Embryology 12mo, 1 25-
Smith's Lecture Notes on Chemistry for Dental Students Svo, 2 50
* Whipple's Tyhpoid Fever Large 12mo, 3 OO
* WoodhuU's Military Hygiene for Officers of the Line Large 12mo, 1 50
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Worcester and Atkinson's Small Hospitals Establishment and Maintenance,
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